517 results on '"Forbes, Andrew"'
Search Results
2. Roadmap on computational methods in optical imaging and holography [invited].
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Rosen, Joseph, Alford, Simon, Allan, Blake, Anand, Vijayakumar, Arnon, Shlomi, Arockiaraj, Francis Gracy, Art, Jonathan, Bai, Bijie, Balasubramaniam, Ganesh M., Birnbaum, Tobias, Bisht, Nandan S., Blinder, David, Cao, Liangcai, Chen, Qian, Chen, Ziyang, Dubey, Vishesh, Egiazarian, Karen, Ercan, Mert, Forbes, Andrew, and Gopakumar, G.
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HIGH resolution imaging ,OPTICAL images ,ARCHITECTS ,ALGORITHMS ,HOLOGRAPHY - Abstract
Computational methods have been established as cornerstones in optical imaging and holography in recent years. Every year, the dependence of optical imaging and holography on computational methods is increasing significantly to the extent that optical methods and components are being completely and efficiently replaced with computational methods at low cost. This roadmap reviews the current scenario in four major areas namely incoherent digital holography, quantitative phase imaging, imaging through scattering layers, and super-resolution imaging. In addition to registering the perspectives of the modern-day architects of the above research areas, the roadmap also reports some of the latest studies on the topic. Computational codes and pseudocodes are presented for computational methods in a plug-and-play fashion for readers to not only read and understand but also practice the latest algorithms with their data. We believe that this roadmap will be a valuable tool for analyzing the current trends in computational methods to predict and prepare the future of computational methods in optical imaging and holography. [ABSTRACT FROM AUTHOR]
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- 2024
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3. Maintaining the validity of inference from linear mixed models in stepped-wedge cluster randomized trials under misspecified random-effects structures.
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Ouyang, Yongdong, Taljaard, Monica, Forbes, Andrew B, and Li, Fan
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CLUSTER randomized controlled trials ,INFERENTIAL statistics ,DEGREES of freedom ,CLUSTER analysis (Statistics) ,POCKETKNIVES - Abstract
Linear mixed models are commonly used in analyzing stepped-wedge cluster randomized trials. A key consideration for analyzing a stepped-wedge cluster randomized trial is accounting for the potentially complex correlation structure, which can be achieved by specifying random-effects. The simplest random effects structure is random intercept but more complex structures such as random cluster-by-period, discrete-time decay, and more recently, the random intervention structure, have been proposed. Specifying appropriate random effects in practice can be challenging: assuming more complex correlation structures may be reasonable but they are vulnerable to computational challenges. To circumvent these challenges, robust variance estimators may be applied to linear mixed models to provide consistent estimators of standard errors of fixed effect parameters in the presence of random-effects misspecification. However, there has been no empirical investigation of robust variance estimators for stepped-wedge cluster randomized trials. In this article, we review six robust variance estimators (both standard and small-sample bias-corrected robust variance estimators) that are available for linear mixed models in R, and then describe a comprehensive simulation study to examine the performance of these robust variance estimators for stepped-wedge cluster randomized trials with a continuous outcome under different data generators. For each data generator, we investigate whether the use of a robust variance estimator with either the random intercept model or the random cluster-by-period model is sufficient to provide valid statistical inference for fixed effect parameters, when these working models are subject to random-effect misspecification. Our results indicate that the random intercept and random cluster-by-period models with robust variance estimators performed adequately. The CR3 robust variance estimator (approximate jackknife) estimator, coupled with the number of clusters minus two degrees of freedom correction, consistently gave the best coverage results, but could be slightly conservative when the number of clusters was below 16. We summarize the implications of our results for the linear mixed model analysis of stepped-wedge cluster randomized trials and offer some practical recommendations on the choice of the analytic model. [ABSTRACT FROM AUTHOR]
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- 2024
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4. A simple and effective method for simulating nested exchangeable correlated binary data for longitudinal cluster randomised trials.
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Bowden, Rhys A., Kasza, Jessica, and Forbes, Andrew B.
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MULTILEVEL models ,RANDOM variables ,LONGITUDINAL method ,CROSSOVER trials ,STATISTICS - Abstract
Background: Simulation is an important tool for assessing the performance of statistical methods for the analysis of data and for the planning of studies. While methods are available for the simulation of correlated binary random variables, all have significant practical limitations for simulating outcomes from longitudinal cluster randomised trial designs, such as the cluster randomised crossover and the stepped wedge trial designs. For these trial designs as the number of observations in each cluster increases these methods either become computationally infeasible or their range of allowable correlations rapidly shrinks to zero. Methods: In this paper we present a simple method for simulating binary random variables with a specified vector of prevalences and correlation matrix. This method allows for the outcome prevalence to change due to treatment or over time, and for a 'nested exchangeable' correlation structure, in which observations in the same cluster are more highly correlated if they are measured in the same time period than in different time periods, and where different individuals are measured in each time period. This means that our method is also applicable to more general hierarchical clustered data contexts, such as students within classrooms within schools. The method is demonstrated by simulating 1000 datasets with parameters matching those derived from data from a cluster randomised crossover trial assessing two variants of stress ulcer prophylaxis. Results: Our method is orders of magnitude faster than the most well known general simulation method while also allowing a much wider range of correlations than alternative methods. An implementation of our method is available in an R package NestBin. Conclusions: This simulation method is the first to allow for practical and efficient simulation of large datasets of binary outcomes with the commonly used nested exchangeable correlation structure. This will allow for much more effective testing of designs and inference methods for longitudinal cluster randomised trials with binary outcomes. [ABSTRACT FROM AUTHOR]
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- 2024
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5. Advances in Quantum Imaging with Machine Intelligence.
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Moodley, Chané and Forbes, Andrew
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ARTIFICIAL intelligence ,PHOTON detectors ,DEEP learning ,PHOTONS ,CAMERAS - Abstract
Quantum imaging exemplifies the fascinating and counter‐intuitive nature of the quantum world, where non‐local correlations are exploited for imaging of objects by remote and non‐interacting photons. The field has exploded of late, driven by advances in our fundamental understanding of these processes, but also by advances in technology, for instance, efficient single photon detectors and cameras. Accelerating the progress is the nascent intersection of quantum imaging with artificial intelligence and machine learning, promising enhanced speed and quality of quantum images. This review provides a comprehensive overview of the rapidly evolving field of quantum imaging with a specific focus on the intersection of quantum ghost imaging with artificial intelligence and machine learning techniques. The seminal advances made to date and the open challenges are highlighted, and the likely trajectory for the future is outlined. [ABSTRACT FROM AUTHOR]
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- 2024
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6. Investigation of bias due to selective inclusion of study effect estimates in meta‐analyses of nutrition research.
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Kanukula, Raju, McKenzie, Joanne E., Bero, Lisa, Dai, Zhaoli, McDonald, Sally, Kroeger, Cynthia M., Korevaar, Elizabeth, Forbes, Andrew, and Page, Matthew J.
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STATISTICAL sampling ,STOCHASTIC processes - Abstract
We aimed to explore, in a sample of systematic reviews (SRs) with meta‐analyses of the association between food/diet and health‐related outcomes, whether systematic reviewers selectively included study effect estimates in meta‐analyses when multiple effect estimates were available. We randomly selected SRs of food/diet and health‐related outcomes published between January 2018 and June 2019. We selected the first presented meta‐analysis in each review (index meta‐analysis), and extracted from study reports all study effect estimates that were eligible for inclusion in the meta‐analysis. We calculated the Potential Bias Index (PBI) to quantify and test for evidence of selective inclusion. The PBI ranges from 0 to 1; values above or below 0.5 suggest selective inclusion of effect estimates more or less favourable to the intervention, respectively. We also compared the index meta‐analytic estimate to the median of a randomly constructed distribution of meta‐analytic estimates (i.e., the estimate expected when there is no selective inclusion). Thirty‐nine SRs with 312 studies were included. The estimated PBI was 0.49 (95% CI 0.42–0.55), suggesting that the selection of study effect estimates from those reported was consistent with a process of random selection. In addition, the index meta‐analytic effect estimates were similar, on average, to what we would expect to see in meta‐analyses generated when there was no selective inclusion. Despite this, we recommend that systematic reviewers report the methods used to select effect estimates to include in meta‐analyses, which can help readers understand the risk of selective inclusion bias in the SRs. [ABSTRACT FROM AUTHOR]
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- 2024
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7. Advancing randomized controlled trial methodologies: The place of innovative trial design in eating disorders research.
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Ryan, Elizabeth G., Gao, Caroline X., Grantham, Kelsey L., Thao, Le Thi Phuong, Charles‐Nelson, Anaïs, Bowden, Rhys, Herschtal, Alan, Lee, Katherine J., Forbes, Andrew B., Heritier, Stephane, Phillipou, Andrea, and Wolfe, Rory
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DIFFUSION of innovations ,HUMAN research subjects ,STATISTICAL sampling ,RANDOMIZED controlled trials ,EATING disorders ,EXPERIMENTAL design ,HEALTH outcome assessment ,QUALITY assurance - Abstract
Randomized controlled trials can be used to generate evidence on the efficacy and safety of new treatments in eating disorders research. Many of the trials previously conducted in this area have been deemed to be of low quality, in part due to a number of practical constraints. This article provides an overview of established and more innovative clinical trial designs, accompanied by pertinent examples, to highlight how design choices can enhance flexibility and improve efficiency of both resource allocation and participant involvement. Trial designs include individually randomized, cluster randomized, and designs with randomizations at multiple time points and/or addressing several research questions (master protocol studies). Design features include the use of adaptations and considerations for pragmatic or registry‐based trials. The appropriate choice of trial design, together with rigorous trial conduct, reporting and analysis, can establish high‐quality evidence to advance knowledge in the field. It is anticipated that this article will provide a broad and contemporary introduction to trial designs and will help researchers make informed trial design choices for improved testing of new interventions in eating disorders. Public Significance: There is a paucity of high quality randomized controlled trials that have been conducted in eating disorders, highlighting the need to identify where efficiency gains in trial design may be possible to advance the eating disorder research field. We provide an overview of some key trial designs and features which may offer solutions to practical constraints and increase trial efficiency. [ABSTRACT FROM AUTHOR]
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- 2024
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8. Quantum cryptography with structured photons.
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Forbes, Andrew, Youssef, Mostafa, Singh, Sachleen, Nape, Isaac, and Ung, Bora
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QUANTUM cryptography ,PHOTONS ,DEGREES of freedom ,BIT rate ,QUANTUM states ,KNOWLEDGE transfer ,EAVESDROPPING - Abstract
Quantum photonic platforms have proven to be essential in realizing fundamentally secure quantum transfer of information, with commercially ready systems already deployed in municipal and terrestrial links. The drive toward higher bit rates and robustness to eavesdropping and noisy channels has focused attention on moving from the present two-dimensional quantum states of polarization, to harnessing all of light's degrees of freedom for multi-dimensional quantum coding with structured photons. In this Perspective, we outline the present state-of-the-art in achieving this control with spatial modes of light, both as single photon and entangled states, highlight the open challenges that remain, and consider the roadmap that might see its full potential realized. [ABSTRACT FROM AUTHOR]
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- 2024
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9. Non-local skyrmions as topologically resilient quantum entangled states of light.
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Ornelas, Pedro, Nape, Isaac, de Mello Koch, Robert, and Forbes, Andrew
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In the early 1960s, inspired by developing notions of topological structure, Tony Skyrme suggested that sub-atomic particles can be described as natural excitations of a single quantum field. Although never adopted for its intended purpose, the notion of a skyrmion as a topologically stable field configuration has proven to be highly versatile, finding application in condensed-matter physics, acoustics and more recently, optics, but it has been realized as localized fields and particles in all instances. Here we report the first non-local quantum entangled state with a non-trivial topology that is skyrmionic in nature, even though each individual photon has no salient topological structure. We demonstrate how the topology makes such quantum states robust to smooth deformations of the wavefunction, remaining intact until the entanglement itself vanishes. Our work points to a nascent connection between entanglement classes and topology, opens exciting questions into the nature of map-preserving quantum channels and offers a promising avenue for the preservation of quantum information by topologically engineered quantum states that persist even when entanglement is fragile. A skyrmion is a topologically stable field configuration. A non-local skyrmion, which has been hitherto elusive in condensed-matter physics, is realized by using entangled photons with a non-trivial topology. The connection between the notions of topology and entanglement is investigated, revealing topological invariance even when entanglement is fragile. [ABSTRACT FROM AUTHOR]
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- 2024
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10. Large quantum alphabets with a tiny footprint.
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Nothlawala, Fazilah and Forbes, Andrew
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- 2024
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11. Magnetotransport in ferromagnetic Fe2Ge semimetallic thin films.
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Forbes, Andrew W., Bhattarai, Niraj, Gassen, Christopher, Saqat, Raghad S. H., Pegg, Ian L., and Philip, John
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THIN films ,MOLECULAR beam epitaxy ,CHARGE carrier mobility ,SPIN polarization ,ANOMALOUS Hall effect ,MAGNETORESISTANCE ,X-ray diffraction - Abstract
Thin films of ferromagnet F e 2 Ge were grown via molecular beam epitaxy, and their electrical and magneto-transport properties were measured for the first time. X-ray diffraction and vibrating sample magnetometry measurements confirmed the crystalline ferromagnetic F e 2 Ge phase. The observed high-temperature maximum in the longitudinal resistivity, as well as the observed suppression of electron–magnon scattering at low temperatures, points to the presence of strong spin polarization in this material. Measurements of the Hall resistivity, ρ x y , show contributions from both the ordinary Hall effect and the anomalous Hall effect, ρ x y A H , from which we determined the charge carrier concentration and mobility. Measurements also show a small negative magnetoresistance in both the longitudinal and transverse geometries. F e 2 Ge holds promise as a useful spintronic material, especially for its semiconductor compatibility. [ABSTRACT FROM AUTHOR]
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- 2022
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12. Comparison of statistical methods used to meta-analyse results from interrupted time series studies: an empirical study.
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Korevaar, Elizabeth, Turner, Simon L., Forbes, Andrew B., Karahalios, Amalia, Taljaard, Monica, and McKenzie, Joanne E.
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TIME series analysis ,EMPIRICAL research ,DATA libraries ,HEALTH policy ,CONFIDENCE intervals - Abstract
Background: The Interrupted Time Series (ITS) is a robust design for evaluating public health and policy interventions or exposures when randomisation may be infeasible. Several statistical methods are available for the analysis and meta-analysis of ITS studies. We sought to empirically compare available methods when applied to real-world ITS data. Methods: We sourced ITS data from published meta-analyses to create an online data repository. Each dataset was re-analysed using two ITS estimation methods. The level- and slope-change effect estimates (and standard errors) were calculated and combined using fixed-effect and four random-effects meta-analysis methods. We examined differences in meta-analytic level- and slope-change estimates, their 95% confidence intervals, p-values, and estimates of heterogeneity across the statistical methods. Results: Of 40 eligible meta-analyses, data from 17 meta-analyses including 282 ITS studies were obtained (predominantly investigating the effects of public health interruptions (88%)) and analysed. We found that on average, the meta-analytic effect estimates, their standard errors and between-study variances were not sensitive to meta-analysis method choice, irrespective of the ITS analysis method. However, across ITS analysis methods, for any given meta-analysis, there could be small to moderate differences in meta-analytic effect estimates, and important differences in the meta-analytic standard errors. Furthermore, the confidence interval widths and p-values for the meta-analytic effect estimates varied depending on the choice of confidence interval method and ITS analysis method. Conclusions: Our empirical study showed that meta-analysis effect estimates, their standard errors, confidence interval widths and p-values can be affected by statistical method choice. These differences may importantly impact interpretations and conclusions of a meta-analysis and suggest that the statistical methods are not interchangeable in practice. [ABSTRACT FROM AUTHOR]
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- 2024
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13. The staircase cluster randomised trial design: A pragmatic alternative to the stepped wedge.
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Grantham, Kelsey L, Forbes, Andrew B, Hooper, Richard, and Kasza, Jessica
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This article introduces the 'staircase' design, derived from the zigzag pattern of steps along the diagonal of a stepped wedge design schematic where clusters switch from control to intervention conditions. Unlike a complete stepped wedge design where all participating clusters must collect and provide data for the entire trial duration, clusters in a staircase design are only required to be involved and collect data for a limited number of pre- and post-switch periods. This could alleviate some of the burden on participating clusters, encouraging involvement in the trial and reducing the likelihood of attrition. Staircase designs are already being implemented, although in the absence of a dedicated methodology, approaches to sample size and power calculations have been inconsistent. We provide expressions for the variance of the treatment effect estimator when a linear mixed model for an outcome is assumed for the analysis of staircase designs in order to enable appropriate sample size and power calculations. These include explicit variance expressions for basic staircase designs with one pre- and one post-switch measurement period. We show how the variance of the treatment effect estimator is related to key design parameters and demonstrate power calculations for examples based on a real trial. [ABSTRACT FROM AUTHOR]
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- 2024
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14. Speciation in kleptoparasites of oak gall wasps often correlates with shifts into new tree habitats, tree organs, or gall morphospace.
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Ward, Anna K G, Zhang, Y Miles, Brown, Guerin E, Hippee, Alaine C, Prior, Kirsten M, Rollins, Shannon, Sierra, Nicolas, Sheikh, Sofia I, Tribull, Carly M, and Forbes, Andrew A
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GALL wasps ,GALL midges ,GENETIC speciation ,INSECT parasites ,PLANT species ,TREES - Abstract
Host shifts to new plant species can drive speciation for plant-feeding insects, but how commonly do host shifts also drive diversification for the parasites of those same insects? Oak gall wasps induce galls on oak trees and shifts to novel tree hosts and new tree organs have been implicated as drivers of oak gall wasp speciation. Gall wasps are themselves attacked by many insect parasites, which must find their hosts on the correct tree species and organ, but also must navigate the morphologically variable galls with which they interact. Thus, we ask whether host shifts to new trees, organs, or gall morphologies correlate with gall parasite diversification. We delimit species and infer phylogenies for two genera of gall kleptoparasites, Synergus and Ceroptres , reared from a variety of North American oak galls. We find that most species were reared from galls induced by just one gall wasp species, and no parasite species was reared from galls of more than four species. Most kleptoparasite divergence events correlate with shifts to non-ancestral galls. These shifts often involved changes in tree habitat, gall location, and gall morphology. Host shifts are thus implicated in driving diversification for both oak gall wasps and their kleptoparasitic associates. [ABSTRACT FROM AUTHOR]
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- 2024
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15. Evaluation of statistical methods used to meta‐analyse results from interrupted time series studies: A simulation study.
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Korevaar, Elizabeth, Turner, Simon L., Forbes, Andrew B., Karahalios, Amalia, Taljaard, Monica, and McKenzie, Joanne E.
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FIXED effects model ,TIME series analysis ,EVALUATION methodology ,STATISTICAL decision making ,HEALTH policy - Abstract
Interrupted time series (ITS) are often meta‐analysed to inform public health and policy decisions but examination of the statistical methods for ITS analysis and meta‐analysis in this context is limited. We simulated meta‐analyses of ITS studies with continuous outcome data, analysed the studies using segmented linear regression with two estimation methods [ordinary least squares (OLS) and restricted maximum likelihood (REML)], and meta‐analysed the immediate level‐ and slope‐change effect estimates using fixed‐effect and (multiple) random‐effects meta‐analysis methods. Simulation design parameters included varying series length; magnitude of lag‐1 autocorrelation; magnitude of level‐ and slope‐changes; number of included studies; and, effect size heterogeneity. All meta‐analysis methods yielded unbiased estimates of the interruption effects. All random effects meta‐analysis methods yielded coverage close to the nominal level, irrespective of the ITS analysis method used and other design parameters. However, heterogeneity was frequently overestimated in scenarios where the ITS study standard errors were underestimated, which occurred for short series or when the ITS analysis method did not appropriately account for autocorrelation. The performance of meta‐analysis methods depends on the design and analysis of the included ITS studies. Although all random effects methods performed well in terms of coverage, irrespective of the ITS analysis method, we recommend the use of effect estimates calculated from ITS methods that adjust for autocorrelation when possible. Doing so will likely to lead to more accurate estimates of the heterogeneity variance. [ABSTRACT FROM AUTHOR]
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- 2023
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16. Massed v. standard prolonged exposure therapy for PTSD in military personnel and veterans: 12-month follow-up of a non-inferiority randomised controlled trial.
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Dell, Lisa, Sbisa, Alyssa M., Forbes, Andrew, O'Donnell, Meaghan, Bryant, Richard, Hodson, Stephanie, Morton, David, Battersby, Malcolm, Tuerk, Peter W., Elliott, Peter, Wallace, Duncan, and Forbes, David
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TREATMENT of post-traumatic stress disorder ,RESEARCH ,BEHAVIOR therapy ,RANDOMIZED controlled trials ,COMPARATIVE studies ,PRE-tests & post-tests ,TREATMENT effectiveness ,SEVERITY of illness index ,MENTAL depression ,QUALITY of life ,RESEARCH funding ,VETERANS ,STATISTICAL sampling ,ANXIETY ,ANGER ,PEOPLE with disabilities ,MILITARY personnel - Abstract
Background: The utilisation of massed therapy for treating posttraumatic stress disorder (PTSD) is gaining strength, especially prolonged exposure. However, it is unknown whether massed prolonged exposure (MPE) is non-inferior to standard prolonged exposure (SPE) protocols in the long term. The current study aimed to assess whether MPE was non-inferior to SPE at 12 months post-treatment, and to ascertain changes in secondary measure outcomes. Methods: A multi-site non-inferiority randomised controlled trial (RCT) compared SPE with MPE in 12 clinics. The primary outcome was PTSD symptom severity (CAPS-5) at 12 months post-treatment commencement. Secondary outcome measures included symptoms of depression, anxiety, anger, disability, and quality of life at 12 weeks and 12 months post-treatment commencement. Outcome assessors were blinded to treatment allocation. The intention-to-treat sample included 138 Australian military members and veterans and data were analysed for 134 participants (SPE = 71, MPE = 63). Results: Reductions in PTSD severity were maintained at 12 months and MPE remained non-inferior to SPE. Both treatment groups experienced a reduction in depression, anxiety, anger, and improvements in quality of life at 12 weeks and 12 months post-treatment commencement. Treatment effects for self-reported disability in the SPE group at 12 weeks were not maintained, with neither group registering significant effects at 12 months. Conclusions: The emergence of massed protocols for PTSD is an important advancement. The current study provides RCT evidence for the longevity of MPE treatment gains at 12 months post-treatment commencement and demonstrated non-inferiority to SPE. Promisingly, both treatments also significantly reduced the severity of comorbid symptoms commonly occurring alongside PTSD. [ABSTRACT FROM AUTHOR]
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- 2023
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17. Does it decay? Obtaining decaying correlation parameter values from previously analysed cluster randomised trials.
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Kasza, Jessica, Bowden, Rhys, Ouyang, Yongdong, Taljaard, Monica, and Forbes, Andrew B
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TIME measurements ,CONFIDENCE intervals ,SAMPLE size (Statistics) ,DATA analysis - Abstract
A frequently applied assumption in the analysis of data from cluster randomised trials is that the outcomes from all participants within a cluster are equally correlated. That is, the intracluster correlation, which describes the degree of dependence between outcomes from participants in the same cluster, is the same for each pair of participants in a cluster. However, recent work has discussed the importance of allowing for this correlation to decay as the time between the measurement of participants in a cluster increases. Incorrect omission of such a decay can lead to under-powered studies, and confidence intervals for estimated treatment effects can be too narrow or too wide, depending on the characteristics of the design. When planning studies, researchers often rely on previously reported analyses of trials to inform their choice of intracluster correlation. However, most reported analyses of clustered data do not incorporate a correlation decay. Thus, often all that is available are estimates of intracluster correlations obtained under the potentially incorrect assumption of no decay. In this article, we show that it is possible to use intracluster correlation values obtained from models that incorrectly omit a decay to inform plausible choices of decaying correlations. Our focus is on intracluster correlation estimates for continuous outcomes obtained by fitting linear mixed models with exchangeable or block-exchangeable correlation structures. We describe how plausible values for decaying correlations may be obtained given these estimated intracluster correlations. An online app is presented that allows users to obtain plausible values of the decay, which can be used at the trial planning stage to assess the sensitivity of sample size and power calculations to decaying correlation structures. [ABSTRACT FROM AUTHOR]
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- 2023
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18. Host–enemy interactions provide limited biotic resistance for a range‐expanding species via reduced apparent competition.
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Prior, Kirsten M., Jones, Dylan G., Meadley‐Dunphy, Shannon A., Lee, Susan, Milks, Alyson K., Daughton, Sage, Forbes, Andrew A., and Powell, Thomas H. Q.
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GALL wasps ,SPECIES ,INSECT communities ,GALL midges ,PHENOLOGY ,COMPETITION (Biology) - Abstract
Aim: As species' ranges shift poleward in response to anthropogenic change, they may lose antagonistic interactions if they move into less diverse communities, fail to interact with novel populations or species effectively, or if ancestral interacting populations or species fail to shift synchronously. We leveraged a poleward range expansion in a tractable insect host–enemy community to uncover mechanisms by which altered antagonistic interactions between native and recipient communities contributed to 'high niche opportunities' (limited biotic resistance) for a range‐expanding insect. Location: North America, Pacific Northwest. Methods: We created quantitative insect host–enemy interaction networks by sampling oak gall wasps on 400 trees of a dominant oak species in the native and expanded range of a range‐expanding gall wasp species. We compared host–enemy network structure between regions. We measured traits (phenology, morphology) of galls and interacting parasitoids, predicting greater trait divergence in the expanded range. We measured function relating to host control and explored if altered interactions and traits contributed to reduced function, or biotic resistance. Results: Interaction networks had fewer species in the expanded range and lower complementarity of parasitoid assemblages among host species. While networks were more generalized, interactions with the range‐expanding species were more specialized in the expanded range. Specialist enemies effectively tracked the range‐expanding host, and there was reduced apparent competition with co‐occurring hosts by shared generalist enemies. Phenological divergence of enemy assemblages interacting with the range‐expanding and co‐occurring hosts was greater in the expanded range, potentially contributing to weak apparent competition. Biotic resistance was lower in the expanded range, where fewer parasitoids emerged from galls of the range‐expanding host. Main Conclusions: Changes in interactions with generalist enemies created high niche opportunities, and limited biotic resistance, suggesting weak apparent competition may be a mechanism of enemy release for range‐expanding insects embedded within generalist enemy networks. [ABSTRACT FROM AUTHOR]
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- 2023
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19. Postoperative systemic inflammation after major abdominal surgery: patient‐centred outcomes.
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Bain, C. R., Myles, P. S., Martin, C., Wallace, S., Shulman, M. A., Corcoran, T., Bellomo, R., Peyton, P., Story, D. A., Leslie, K., Forbes, A., Myles, Paul, Bellomo, Rinaldo, Corcoran, Tomas, Christophi, Chris, Forbes, Andrew, Peyton, Phil, Story, David, Leslie, Kate, and Serpell, Jonathan
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ABDOMINAL surgery ,FLUID therapy ,INTENSIVE care units ,ACUTE kidney failure ,CLINICAL medicine ,INFLAMMATION - Abstract
Summary: Postoperative systemic inflammation is strongly associated with surgical outcomes, but its relationship with patient‐centred outcomes is largely unknown. Detection of excessive inflammation and patient and surgical factors associated with adverse patient‐centred outcomes should inform preventative treatment options to be evaluated in clinical trials and current clinical care. This retrospective cohort study analysed prospectively collected data from 3000 high‐risk, elective, major abdominal surgery patients in the restrictive vs. liberal fluid therapy for major abdominal surgery (RELIEF) trial from 47 centres in seven countries from May 2013 to September 2016. The co‐primary endpoints were persistent disability or death up to 90 days after surgery, and quality of recovery using a 15‐item quality of recovery score at days 3 and 30. Secondary endpoints included: 90‐day and 1‐year all‐cause mortality; septic complications; acute kidney injury; unplanned admission to intensive care/high dependency unit; and total intensive care unit and hospital stays. Patients were assigned into quartiles of maximum postoperative C‐reactive protein concentration up to day 3, after multiple imputations of missing values. The lowest (reference) group, quartile 1, C‐reactive protein ≤ 85 mg.l‐1, was compared with three inflammation groups: quartile 2 > 85 mg.l‐1 to 140 mg.l‐1; quartile 3 > 140 mg.l‐1 to 200 mg.l‐1; and quartile 4 > 200 mg.l‐1 to 587 mg.l‐1. Greater postoperative systemic inflammation had a higher adjusted risk ratio (95%CI) of persistent disability or death up to 90 days after surgery, quartile 4 vs. quartile 1 being 1.76 (1.31–2.36), p < 0.001. Increased inflammation was associated with increasing decline in risk‐adjusted estimated medians (95%CI) for quality of recovery, the quartile 4 to quartile 1 difference being ‐14.4 (‐17.38 to ‐10.71), p < 0.001 on day 3, and ‐5.94 (‐8.92 to ‐2.95), p < 0.001 on day 30. Marked postoperative systemic inflammation was associated with increased risk of complications, poor quality of recovery and persistent disability or death up to 90 days after surgery. [ABSTRACT FROM AUTHOR]
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- 2023
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20. Quantum transport of high-dimensional spatial information with a nonlinear detector.
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Sephton, Bereneice, Vallés, Adam, Nape, Isaac, Cox, Mitchell A., Steinlechner, Fabian, Konrad, Thomas, Torres, Juan P., Roux, Filippus S., and Forbes, Andrew
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Information exchange between two distant parties, where information is shared without physically transporting it, is a crucial resource in future quantum networks. Doing so with high-dimensional states offers the promise of higher information capacity and improved resilience to noise, but progress to date has been limited. Here we demonstrate how a nonlinear parametric process allows for arbitrary high-dimensional state projections in the spatial degree of freedom, where a strong coherent field enhances the probability of the process. This allows us to experimentally realise quantum transport of high-dimensional spatial information facilitated by a quantum channel with a single entangled pair and a nonlinear spatial mode detector. Using sum frequency generation we upconvert one of the photons from an entangled pair resulting in high-dimensional spatial information transported to the other. We realise a d = 15 quantum channel for arbitrary photonic spatial modes which we demonstrate by faithfully transferring information encoded into orbital angular momentum, Hermite-Gaussian and arbitrary spatial mode superpositions, without requiring knowledge of the state to be sent. Our demonstration merges the nascent fields of nonlinear control of structured light with quantum processes, offering a new approach to harnessing high-dimensional quantum states, and may be extended to other degrees of freedom too.High-dimensional quantum states allow for several advantages in quantum communication, but protocols such as teleportation require additional entangled photons as the dimension increases. Here, the authors show how to transport a high-dimensional quantum state from a bright coherent laser field to a single photon, using two entangled photons as the quantum channel. [ABSTRACT FROM AUTHOR]
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- 2023
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21. Generalizing the information content for stepped wedge designs: A marginal modeling approach.
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Li, Fan, Kasza, Jessica, Turner, Elizabeth L., Rathouz, Paul J., Forbes, Andrew B., and Preisser, John S.
- Subjects
TRENDS ,WEDGES ,CLUSTER randomized controlled trials ,GENERALIZED estimating equations ,BLOCK designs - Abstract
Stepped wedge trials are increasingly adopted because practical constraints necessitate staggered roll‐out. While a complete design requires clusters to collect data in all periods, resource and patient‐centered considerations may call for an incomplete stepped wedge design to minimize data collection burden. To study incomplete designs, we expand the metric of information content to discrete outcomes. We operate under a marginal model with general link and variance functions, and derive information content expressions when data elements (cells, sequences, periods) are omitted. We show that the centrosymmetric patterns of information content can hold for discrete outcomes with the variance‐stabilizing link function. We perform numerical studies under the canonical link function, and find that while the patterns of information content for cells are approximately centrosymmetric for all examined underlying secular trends, the patterns of information content for sequences or periods are more sensitive to the secular trend, and may be far from centrosymmetric. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
22. Seeing invisible objects with intelligent optics.
- Author
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Nape, Isaac and Forbes, Andrew
- Published
- 2024
- Full Text
- View/download PDF
23. Sample size for partially nested designs and other nested or crossed designs with a continuous outcome when adjusted for baseline.
- Author
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Teerenstra, Steven, Kasza, Jessica, Leontjevas, Ruslan, and Forbes, Andrew B.
- Subjects
SAMPLE size (Statistics) ,CLUSTER randomized controlled trials ,RANDOMIZED controlled trials ,REQUIREMENTS engineering - Abstract
In a randomized controlled trial, outcomes of different subjects may be independent at baseline, but correlated at a follow‐up measurement due to treatment. This treatment‐related clustering at follow‐up can arise for instance because the treatment is given in a group or because subjects are treated individually but by the same therapist (therapist effect). There is substantial literature on the design and analysis of such trials when estimation of the intervention effect is based on a follow‐up measurement (eg, directly after treatment or at a later time point). However, often the baseline measurement of the outcome is highly correlated with the follow‐up measurement, and this information can be used in the analysis. For a randomized design with a baseline and a follow‐up measurement, we compare sample size requirements for analyses with and without adjustment for this baseline measure. We show that adjusting for baseline reduces required sample size. This reduction depends on the variance of the difference between arms at baseline, the variance of this difference at follow‐up, and the correlation between the two. From this, we derive sample size formulas for partially or fully nested designs, and cluster randomized trials with treatment as a partially or fully cross‐classified factor. Also, we discuss situations where clusters are already present at baseline or where treatment by cluster interaction is present. For the partially nested design, we work out practical design considerations (eg, use of content‐matter input, design factors and optimal allocation ratio) and investigate small sample properties of the sample size formula. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
24. The invariance and distortion of vectorial light across a real-world free space link.
- Author
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Peters, Cade, Cox, Mitchell, Drozdov, Alice, and Forbes, Andrew
- Subjects
WEATHER ,ATMOSPHERIC turbulence ,QUANTUM communication ,DEGREES of freedom ,INTERSTELLAR communication ,COMMUNITIES - Abstract
Vectorial structured light, where the polarization is inhomogeneously distributed in space, has found a myriad of applications in both 2D and 3D optical fields. Here, we present an experimental study of the invariance and distortion of vectorial light through a real-world medium of atmospheric turbulence. We show that the amplitude and polarization structure are both severely distorted by the turbulent medium, yet the non-separability of these two degrees of freedom remains invariant. We monitor this invariance under a range of beam types and atmospheric conditions, over extended time periods, revealing the unitary nature of atmospheric turbulence in our experiment. Our results provide conclusive evidence that invariance and distortion are not mutually exclusive and that the degree of classical entanglement remains unaltered through such channels, and will be of interest to the large community interested in classical and quantum communication in free space. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
25. The impact of iterative removal of low-information cluster-period cells from a stepped wedge design.
- Author
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Rezaei-Darzi, Ehsan, Grantham, Kelsey L., Forbes, Andrew B., and Kasza, Jessica
- Subjects
WEDGES ,TREATMENT effectiveness - Abstract
Background: Standard stepped wedge trials, where clusters switch from the control to the intervention condition in a staggered manner, can be costly and burdensome. Recent work has shown that the amount of information contributed by each cluster in each period differs, with some cluster-periods contributing a relatively small amount of information. We investigate the patterns of the information content of cluster-period cells upon iterative removal of low-information cells, assuming a model for continuous outcomes with constant cluster-period size, categorical time period effects, and exchangeable and discrete-time decay intracluster correlation structures. Methods: We sequentially remove pairs of "centrosymmetric" cluster-period cells from an initially complete stepped wedge design which contribute the least amount of information to the estimation of the treatment effect. At each iteration, we update the information content of the remaining cells, determine the pair of cells with the lowest information content, and repeat this process until the treatment effect cannot be estimated. Results: We demonstrate that as more cells are removed, more information is concentrated in the cells near the time of the treatment switch, and in "hot-spots" in the corners of the design. For the exchangeable correlation structure, removing the cells from these hot-spots leads to a marked reduction in study precision and power, however the impact of this is lessened for the discrete-time decay structure. Conclusions: Removing cluster-period cells distant from the time of the treatment switch may not lead to large reductions in precision or power, implying that certain incomplete designs may be almost as powerful as complete designs. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
26. Effect estimates can be accurately calculated with data digitally extracted from interrupted time series graphs.
- Author
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Turner, Simon Lee, Korevaar, Elizabeth, Cumpston, Miranda S., Kanukula, Raju, Forbes, Andrew B., and McKenzie, Joanne E.
- Subjects
DATA extraction ,HEALTH policy ,REGRESSION analysis - Abstract
Interrupted time series (ITS) studies are frequently used to examine the impact of population‐level interventions or exposures. Systematic reviews with meta‐analyses including ITS designs may inform public health and policy decision‐making. Re‐analysis of ITS may be required for inclusion in meta‐analysis. While publications of ITS rarely provide raw data for re‐analysis, graphs are often included, from which time series data can be digitally extracted. However, the accuracy of effect estimates calculated from data digitally extracted from ITS graphs is currently unknown. Forty‐three ITS with available datasets and time series graphs were included. Time series data from each graph was extracted by four researchers using digital data extraction software. Data extraction errors were analysed. Segmented linear regression models were fitted to the extracted and provided datasets, from which estimates of immediate level and slope change (and associated statistics) were calculated and compared across the datasets. Although there were some data extraction errors of time points, primarily due to complications in the original graphs, they did not translate into important differences in estimates of interruption effects (and associated statistics). Using digital data extraction to obtain data from ITS graphs should be considered in reviews including ITS. Including these studies in meta‐analyses, even with slight inaccuracy, is likely to outweigh the loss of information from non‐inclusion. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
27. Effect of massed v. standard prolonged exposure therapy on PTSD in military personnel and veterans: a non-inferiority randomised controlled trial.
- Author
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Dell, Lisa, Sbisa, Alyssa M., Forbes, Andrew, O'Donnell, Meaghan, Bryant, Richard, Hodson, Stephanie, Morton, David, Battersby, Malcolm, Tuerk, Peter W., Wallace, Duncan, and Forbes, David
- Subjects
TREATMENT of post-traumatic stress disorder ,RESEARCH ,CONFIDENCE intervals ,BEHAVIOR therapy ,PSYCHOLOGY of veterans ,TREATMENT effectiveness ,SEVERITY of illness index ,RANDOMIZED controlled trials ,COMPARATIVE studies ,DESCRIPTIVE statistics ,RESEARCH funding ,PSYCHOLOGY of military personnel - Abstract
Background: A short, effective therapy for posttraumatic stress disorder (PTSD) could decrease barriers to implementation and uptake, reduce dropout, and ameliorate distressing symptoms in military personnel and veterans. This non-inferiority RCT evaluated the efficacy of 2-week massed prolonged exposure (MPE) therapy compared to standard 10-week prolonged exposure (SPE), the current gold standard treatment, in reducing PTSD severity in both active serving and veterans in a real-world health service system. Methods: This single-blinded multi-site non-inferiority RCT took place in 12 health clinics across Australia. The primary outcome was PTSD symptom severity measured by the Clinician-Administered PTSD Scale for DSM-5 (CAPS-5) at 12 weeks. 138 military personnel and veterans with PTSD were randomised. 71 participants were allocated to SPE, with 63 allocated to MPE. Results: The intention-to-treat sample included 138 participants, data were analysed for 134 participants (88.1% male, M = 46 years). The difference between the mean MPE and SPE group PTSD scores from baseline to 12 weeks-post therapy was 0.94 [95% confidence interval (CI) −4.19 to +6.07]. The upper endpoint of the 95% CI was below +7, indicating MPE was non-inferior to SPE. Significant rates of loss of PTSD diagnosis were found for both groups (MPE 53.8%, SPE 54.1%). Dropout rates were 4.8% (MPE) and 16.9% (SPE). Conclusions: MPE was non-inferior to SPE in significantly reducing symptoms of PTSD. Significant reductions in symptom severity, low dropout rates, and loss of diagnosis indicate MPE is a feasible, accessible, and effective treatment. Findings demonstrate novel methods to deliver gold-standard treatments for PTSD should be routinely considered. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
28. A Robust Basis for Multi‐Bit Optical Communication with Vectorial Light.
- Author
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Singh, Keshaan, Nape, Isaac, Buono, Wagner Tavares, Dudley, Angela, and Forbes, Andrew
- Subjects
OPTICAL communications ,AMPLITUDE modulation ,ATMOSPHERIC turbulence ,VECTOR beams ,KNOWLEDGE transfer - Abstract
Increasing the information capacity of communication channels is a pressing need, driven by growing data demands and the consequent impending data crunch with existing modulation schemes. In this regard, mode division multiplexing (MDM), where spatial modes of light form the encoding basis, has enormous potential but is impeded by noise due to imperfect channels. Here, this challenge is overcome by breaking the existing MDM paradigm of using the modes themselves as a discrete basis and instead exploiting the polarization inhomogeneity (vectorness) of vectorial light as the information carrier. It is shown that this vectorness communication basis is completely impervious to channel noise, which is verified by near perfect data fidelity maintained in multi‐bit information transfer through atmospheric turbulence, with negligible changes on the order of 1%. This allows for demonstration of a new state‐of‐the‐art of 50 vectorial modes in a communications channel with little cross‐talk. This approach replaces conventional amplitude modulation with a novel modal alternative for potentially orders of magnitude channel information enhancement, offering a new paradigm to exploiting the spatial mode basis for optical communication. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
29. Quantum structured light in high dimensions.
- Author
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Nape, Isaac, Sephton, Bereneice, Ornelas, Pedro, Moodley, Chane, and Forbes, Andrew
- Subjects
PHOTONS ,QUANTUM mechanics ,DEGREES of freedom ,QUANTUM information science ,HILBERT space - Abstract
Structured light has become topical of late, where controlling light in all its degrees of freedom has offered novel states of light long predicted, enhanced functionality in applications, and a modern toolbox for probing fundamental science. Structuring light as single photons and entangled states allows the spatial modes of light to be used to encode a large alphabet, accessing high dimensional Hilbert spaces for fundamental tests of quantum mechanics and improved quantum information processing tasks. In this tutorial, we outline the basic concepts of high dimensional quantum states expressed in a basis of spatial modes (structured light) and explain how to create, control, and detect such quantum states in the laboratory with a focus on transverse spatial modes such as the orbital angular momentum and pixel (position) modes. Finally, we highlight some example applications of such quantum structured light, from communications to imaging. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
30. Mental health and wellbeing of health and aged care workers in Australia, May 2021 – June 2022: a longitudinal cohort study.
- Author
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McGuinness, Sarah L, Eades, Owen, Grantham, Kelsey L, Zhong, Shannon, Johnson, Josphin, Cameron, Peter A, Forbes, Andrew B, Fisher, Jane RW, Hodgson, Carol L, Kasza, Jessica, Kelsall, Helen, Kirkman, Maggie, Russell, Grant M, Russo, Philip L, Sim, Malcolm R, Singh, Kasha, Skouteris, Helen, Smith, Karen, Stuart, Rhonda L, and Trauer, James M
- Subjects
WELL-being ,MENTAL health ,POST-traumatic stress ,GENERALIZED anxiety disorder ,MENTAL health services ,MASLACH Burnout Inventory ,LONGITUDINAL method ,AMBULANCES - Abstract
Objectives: To assess the mental health and wellbeing of health and aged care workers in Australia during the second and third years of the coronavirus disease 2019 (COVID‐19) pandemic, overall and by occupation group. Design, setting, participants: Longitudinal cohort study of health and aged care workers (ambulance, hospitals, primary care, residential aged care) in Victoria: May–July 2021 (survey 1), October–December 2021 (survey 2), and May–June 2022 (survey 3). Main outcome measures: Proportions of respondents (adjusted for age, gender, socio‐economic status) reporting moderate to severe symptoms of depression (Patient Health Questionnaire‐9, PHQ‐9), anxiety (Generalized Anxiety Disorder scale, GAD‐7), or post‐traumatic stress (Impact of Event Scale‐6, IES‐6), burnout (abbreviated Maslach Burnout Inventory, aMBI), or high optimism (10‐point visual analogue scale); mean scores (adjusted for age, gender, socio‐economic status) for wellbeing (Personal Wellbeing Index–Adult, PWI‐A) and resilience (Connor Davidson Resilience Scale 2, CD‐RISC‐2). Results: A total of 1667 people responded to at least one survey (survey 1, 989; survey 2, 1153; survey 3, 993; response rate, 3.3%). Overall, 1211 survey responses were from women (72.6%); most respondents were hospital workers (1289, 77.3%) or ambulance staff (315, 18.9%). The adjusted proportions of respondents who reported moderate to severe symptoms of depression (survey 1, 16.4%; survey 2, 22.6%; survey 3, 19.2%), anxiety (survey 1, 8.8%; survey 2, 16.0%; survey 3, 11.0%), or post‐traumatic stress (survey 1, 14.6%; survey 2, 35.1%; survey 3, 14.9%) were each largest for survey 2. The adjusted proportions of participants who reported moderate to severe symptoms of burnout were higher in surveys 2 and 3 than in survey 1, and the proportions who reported high optimism were smaller in surveys 2 and 3 than in survey 1. Adjusted mean scores for wellbeing and resilience were similar at surveys 2 and 3 and lower than at survey 1. The magnitude but not the patterns of change differed by occupation group. Conclusion: Burnout was more frequently reported and mean wellbeing and resilience scores were lower in mid‐2022 than in mid‐2021 for Victorian health and aged care workers who participated in our study. Evidence‐based mental health and wellbeing programs for workers in health care organisations are needed. Trial registration: Australian New Zealand Clinical Trials Registry: ACTRN12621000533897 (observational study; retrospective). [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
31. Extensive regional variation in the phenology of insects and their response to temperature across North America.
- Author
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Dunn, Peter O., Ahmed, Insiyaa, Armstrong, Elise, Barlow, Natasha, Barnard, Malcolm A., Bélisle, Marc, Benson, Thomas J., Berzins, Lisha L., Boynton, Chloe K., Brown, T. Anders, Cady, Melissa, Cameron, Kyle, Chen, Xuan, Clark, Robert G., Clotfelter, Ethan D., Cromwell, Kara, Dawson, Russell D., Denton, Elsie, Forbes, Andrew, and Fowler, Kendrick
- Subjects
INSECT phenology ,PLANT phenology ,CLIMATE change models ,INSECT populations ,PHENOTYPIC plasticity ,TEMPERATURE - Abstract
Climate change models often assume similar responses to temperatures across the range of a species, but local adaptation or phenotypic plasticity can lead plants and animals to respond differently to temperature in different parts of their range. To date, there have been few tests of this assumption at the scale of continents, so it is unclear if this is a large‐scale problem. Here, we examined the assumption that insect taxa show similar responses to temperature at 96 sites in grassy habitats across North America. We sampled insects with Malaise traps during 2019–2021 (N = 1041 samples) and examined the biomass of insects in relation to temperature and time of season. Our samples mostly contained Diptera (33%), Lepidoptera (19%), Hymenoptera (18%), and Coleoptera (10%). We found strong regional differences in the phenology of insects and their response to temperature, even within the same taxonomic group, habitat type, and time of season. For example, the biomass of nematoceran flies increased across the season in the central part of the continent, but it only showed a small increase in the Northeast and a seasonal decline in the Southeast and West. At a smaller scale, insect biomass at different traps operating on the same days was correlated up to ~75 km apart. Large‐scale geographic and phenological variation in insect biomass and abundance has not been studied well, and it is a major source of controversy in previous analyses of insect declines that have aggregated studies from different locations and time periods. Our study illustrates that large‐scale predictions about changes in insect populations, and their causes, will need to incorporate regional and taxonomic differences in the response to temperature. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
32. Magnetotransport Study of Dirac Metal FeSn Thin Films Grown on Silicon Substrates.
- Author
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Bhattarai, Niraj, Forbes, Andrew W., Saqat, Raghad S. H., Pegg, Ian L., and Philip, John
- Subjects
THIN films ,SILICON films ,MOLECULAR beam epitaxy ,THICK films ,HALL effect ,IRON alloys ,IRON ,MAGNETOTELLURICS ,NANOWIRES - Abstract
Thin films of iron–tin alloy FeSn are grown on silicon substrates and their structural and transport properties are investigated for the first time. Herein, the molecular beam epitaxy method is used to grow 50 and 30 nm thick FeSn films on silicon substrates containing 10 nm of MgO as a buffer layer. The films are characterized structurally using an X‐ray diffractometer, showing a hexagonal crystal structure with the space group P6/mmm (191). The results from electrical and magnetotransport measurements show these films exhibit characteristics close to metals. Herein, the magnetotransport properties of the thin films which show positive magnetoresistance and sample‐dependent Hall effect with possible multiband transport are further measured. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
33. Experimentally simulating the beam shaping capabilities of piston-type deformable mirrors using a liquid crystal spatial light modulator.
- Author
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Scholes, Stirling, Mohapi, Lehloa, Leach, Jonathan, Forbes, Andrew, and Dudley, Angela
- Subjects
SPATIAL light modulators ,LIQUID crystals ,BESSEL beams ,MIRRORS ,SILICON crystals ,LIQUID silicon - Abstract
The number of mirror segments, mirror geometry and orientation are essential parameters when assessing the beam-shaping capabilities of deformable mirrors. Here, we use a Liquid Crystal on Silicon Spatial Light Modulator (LCoS-SLM) to mimic the mechanical design of a deformable mirror and quantitatively analyse the effect of the number of mirror segments and their geometrical structure on resulting structured modes. Our approach can be used as a test bed prior to designing a deformable mirror for high power beam shaping. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
34. A Study into the Identity, Patterns of Infection and Potential Pathological Effects of Rumen Fluke and the Frequency of Co-Infections with Liver Fluke in Cattle and Sheep.
- Author
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Busin, Valentina, Geddes, Eilidh, Robertson, Gordon, Mitchell, Gillian, Skuce, Philip, Waine, Katie, Millins, Caroline, and Forbes, Andrew
- Subjects
RUMEN (Ruminants) ,LIVER flukes ,CATTLE diseases ,SHEEP diseases ,DISEASE prevalence - Abstract
Rumen fluke (RF) are trematode parasites that have increased in prevalence within European ruminant livestock since the 1990s. Morbidity and mortality can result from the development of juvenile flukes in the duodenum, however, evidence for significant impacts of adult fluke in the rumen of the final host is equivocal. The presence of rumen fluke in Scotland had not previously been quantified, so the purpose of this study was to use historical coprological data collected between 2008 and 2018 at the School of Veterinary Medicine in Glasgow to evaluate the frequency of rumen fluke infection and to compare this with the presence of liver fluke. This analysis showed evidence of adult rumen fluke in 6.6% of samples submitted, with a substantial and significant increase in positive diagnoses from 2016, following which positive rumen fluke diagnoses equaled or slightly outnumbered those of liver fluke. A prospective post-mortem examination study was also carried out to determine the presence of rumen and liver fluke in cattle and sheep, to quantify adult rumen fluke burdens and to assess any pathological changes in the reticulorumen and proximal duodenum associated with infection. The presence of rumen fluke in post-mortem cases was 26.9% (n = 18/67), the majority (66.7%, n = 12/18) with burdens of less than 100 adult rumen flukes. There was no significant difference in mean ruminal papillar density and length in animals with and without adult rumen fluke and no significant gross pathology was observed in the rumen or reticulum. Examination of animals with adult rumen fluke provided no evidence of any consistent associations with acute or chronic inflammatory changes in the duodenum. All rumen fluke collected at necropsy were identified by PCR and sequencing as Calicophoron daubneyi. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
35. Experimental realization and magnetotransport properties of half-metallic Fe2Si.
- Author
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Forbes, Andrew W., Dulal, Rajendra P., Bhattarai, Niraj, Pegg, Ian L., and Philip, John
- Subjects
MOLECULAR beam epitaxy ,CURIE temperature ,SPIN waves ,ATOMIC force microscopy ,SPIN excitations ,HALL effect ,ANOMALOUS Hall effect ,THIN films - Abstract
Thin films of the high Curie temperature intermetallic ferromagnet β - Fe 2 Si were synthesized via molecular beam epitaxy. Investigation using X-ray diffraction and atomic force microscopy shows a hexagonal crystal structure and a smooth topography. Theoretically, Fe 2 Si has been predicted to exhibit uniquely desirable magnetotransport properties. We report on these properties experimentally, including the ordinary Hall coefficient R 0 and anomalous Hall resistivity ρ x y A H . The compound is found to be a soft Heisenberg ferromagnet with temperature dependent magnetization based on the thermal excitation of spin waves. We present a detailed look into the contributions to its longitudinal resistivity, which due to the presence of a spin-flip gap Δ k B , indicating a half-metallic band structure. The correct scaling relations between these components of the resistivity tensor (ρ x x and ρ x y ) are also discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
36. Ecotoxicology in malaria vector control.
- Author
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Forbes, Andrew
- Published
- 2024
- Full Text
- View/download PDF
37. A Tolerance‐Enhanced Spontaneous Parametric Downconversion Source of Bright Entangled Photons.
- Author
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Singh, Sandeep, Kumar, Vimlesh, Ghosh, Anirban, Forbes, Andrew, and Samanta, G. K.
- Subjects
PARAMETRIC downconversion ,PHOTON pairs ,PHOTONS ,QUANTUM states ,QUANTUM optics ,CRYSTAL orientation - Abstract
Spontaneous parametric down‐conversion (SPDC), a primary resource of photonic quantum entangled states, strongly depends on the intrinsic phase matching condition. This makes it susceptible to changes in factors such as the pump wavelength, crystal temperature, and crystal axes orientation. Such intolerance to changing environmental factors prohibits deployment of SPDC‐based sources in non‐ideal environments outside controlled laboratories. Here, a novel system architecture based on a hybrid linear and non‐linear solution that is shown to make the source tolerance‐enhanced without sacrificing brightness. This linear solution is a lens‐axicon pair, judiciously placed, which is tested together with two common non‐linear crystals, quasi‐phase‐matched periodically‐poled KTiOPO4, and birefringent‐phase‐matched BiB3O6. This approach has the benefit of simultaneous tolerance to the environment and high brightness, which is demonstrated by using the proposed architecture as a stable entangled photon source and a spectral brightness as high as 22.58 ± 0.15 kHz mW−1 with a state fidelity of 0.95 ±0.02$\pm \nobreakspace 0.02$, yet requiring a crystal temperature stability of only ±0.8 °C, a 5 × enhanced tolerance as compared to the conventional high brightness SPDC configurations is reported. This solution offers a new approach to deployable high‐brightness quantum sources that are robust to their environment, for instance, in satellite‐based quantum applications. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
38. Time‐Efficient Object Recognition in Quantum Ghost Imaging.
- Author
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Moodley, Chané, Ruget, Alice, Leach, Jonathan, and Forbes, Andrew
- Subjects
MACHINE learning ,IMAGE denoising ,IMAGE recognition (Computer vision) ,OBJECT recognition (Computer vision) ,IMAGE intensifiers ,LOGISTIC regression analysis - Abstract
Acquiring information at the fastest possible rate is often desirable, particularly in quantum ghost imaging which suffers from slow reconstruction speeds. Many computationally intense deep‐learning methods have been implemented in an effort to speed up image acquisition times by retrieving image information. Often over‐looked, machine learning methods can offer the same, if not better, speed up in image acquisition time by an object recognition process. Four machine learning algorithms are implemented and trained on a uniquely generated, noised, and blurred dataset of numerical digits 1 through 9. Of the tested recognition algorithms, logistic regression shows a 10× speed up in image acquisition time with a 99% prediction accuracy. Additionally, this reduction in acquisition time is achieved without any image denoising or enhancement prior to recognition, thereby reducing training and implementation time, as well as the computational intensity of the approach. This method can be implemented in real‐time, requiring only 1/10th of the measurements needed for a general solution, making it ideal for quantum imaging and recognition of light sensitive structure. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
39. Magnetic properties and magnetocaloric effect of (Fe70Ni30)96Mo4 thin films grown by molecular beam epitaxy.
- Author
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Saqat, Raghad S. H., Forbes, Andrew W., Bhattarai, Niraj, Pegg, Ian L., and Philip, John
- Subjects
MOLECULAR beam epitaxy ,MAGNETOCALORIC effects ,MONOMOLECULAR films ,MAGNETIC properties ,THIN films ,MAGNETIC entropy ,HEUSLER alloys - Abstract
Thin films of ferromagnetic (Fe
70 Ni30 )96 Mo4 were grown via molecular beam epitaxy. Their magnetic properties and magnetocaloric effects were investigated. X-ray diffraction and vibrating sample magnetometry measurements confirmed the crystalline ferromagnetic (Fe70 Ni30 )96 Mo4 phase, with a Curie point near room temperature. To determine the suitability of this material for magnetocaloric applications, we observed a large magnetic entropy change with a large temperature span as well as high relative cooling power near Curie temperature comparable to rare-earth-based materials operating near room temperature. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
40. Optical trapping and fluorescence control with vectorial structured light.
- Author
-
Kritzinger, Ané, Forbes, Andrew, and Forbes, Patricia B. C.
- Subjects
QUANTUM dots ,FLUORESCENCE ,OPTICS ,OPTICAL tweezers - Abstract
Here we functionalized micro-scaled polymer beads with nano-scaled quantum dots and demonstrate optical trapping and tweezing, with in-situ fluorescence measurement, in an all-digital all-optical configuration. We outline the chemistry required to facilitate this, from deactivating the optical trapping environment to size, adhesion and agglomeration control. We introduce a novel holographic optical trapping set-up that leverages on vectorially structured light, allowing for the delivery of tuneable forms of light from purely scalar to purely vector, including propagation invariant flat-top beams for uniform illumination and tailored intensity gradient landscapes. Finally, we show how this has the potential to quench bleaching in a single wavelength trap by linear (spatial mode) rather than non-linear effects, advancing the nascent field of optics for chemistry. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
41. Optical trapping and fluorescence control with vectorial structured light.
- Author
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Kritzinger, Ané, Forbes, Andrew, and Forbes, Patricia B. C.
- Subjects
QUANTUM dots ,FLUORESCENCE ,OPTICS ,OPTICAL tweezers - Abstract
Here we functionalized micro-scaled polymer beads with nano-scaled quantum dots and demonstrate optical trapping and tweezing, with in-situ fluorescence measurement, in an all-digital all-optical configuration. We outline the chemistry required to facilitate this, from deactivating the optical trapping environment to size, adhesion and agglomeration control. We introduce a novel holographic optical trapping set-up that leverages on vectorially structured light, allowing for the delivery of tuneable forms of light from purely scalar to purely vector, including propagation invariant flat-top beams for uniform illumination and tailored intensity gradient landscapes. Finally, we show how this has the potential to quench bleaching in a single wavelength trap by linear (spatial mode) rather than non-linear effects, advancing the nascent field of optics for chemistry. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
42. Highly perturbed genes and hub genes associated with type 2 diabetes in different tissues of adult humans: a bioinformatics analytic workflow.
- Author
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De Silva, Kushan, Demmer, Ryan T., Jönsson, Daniel, Mousa, Aya, Forbes, Andrew, and Enticott, Joanne
- Subjects
TYPE 2 diabetes ,GENE regulatory networks ,RANDOM effects model ,INSULIN synthesis ,GENES ,GENE expression - Abstract
Type 2 diabetes (T2D) has a complex etiology which is not yet fully elucidated. The identification of gene perturbations and hub genes of T2D may deepen our understanding of its genetic basis. We aimed to identify highly perturbed genes and hub genes associated with T2D via an extensive bioinformatics analytic workflow consisting of five steps: systematic review of Gene Expression Omnibus and associated literature; identification and classification of differentially expressed genes (DEGs); identification of highly perturbed genes via meta-analysis; identification of hub genes via network analysis; and downstream analysis of highly perturbed genes and hub genes. Three meta-analytic strategies, random effects model, vote-counting approach, and p value combining approach, were applied. Hub genes were defined as those nodes having above-average betweenness, closeness, and degree in the network. Downstream analyses included gene ontologies, Kyoto Encyclopedia of Genes and Genomes pathways, metabolomics, COVID-19-related gene sets, and Genotype-Tissue Expression profiles. Analysis of 27 eligible microarrays identified 6284 DEGs (4592 downregulated and 1692 upregulated) in four tissue types. Tissue-specific gene expression was significantly greater than tissue non-specific (shared) gene expression. Analyses revealed 79 highly perturbed genes and 28 hub genes. Downstream analyses identified enrichments of shared genes with certain other diabetes phenotypes; insulin synthesis and action-related pathways and metabolomics; mechanistic associations with apoptosis and immunity-related pathways; COVID-19-related gene sets; and cell types demonstrating over- and under-expression of marker genes of T2D. Our approach provided valuable insights on T2D pathogenesis and pathophysiological manifestations. Broader utility of this pipeline beyond T2D is envisaged. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
43. On-chip lasers with twisted light.
- Author
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Forbes, Andrew
- Abstract
A photonic equivalent to disclination in crystals has been used to produce orbital angular momentum laser light directly on-chip, ushering in compact and efficient twisted-light lasers. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
44. Delimiting the cryptic diversity and host preferences of Sycophila parasitoid wasps associated with oak galls using phylogenomic data.
- Author
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Zhang, Yuanmeng M., Sheikh, Sofia I., Ward, Anna K. G., Forbes, Andrew A., Prior, Kirsten M., Stone, Graham N., Gates, Michael W., Egan, Scott P., Zhang, Linyi, Davis, Charles, Weinersmith, Kelly L., Melika, George, and Lucky, Andrea
- Subjects
GALL wasps ,WASPS ,NUMBERS of species ,OAK ,ECOLOGICAL assessment ,SPECIES diversity - Abstract
Cryptic species diversity is a major challenge regarding the species‐rich community of parasitoids attacking oak gall wasps due to a high degree of sexual dimorphism, morphological plasticity, small size and poorly known biology. As such, we know very little about the number of species present, nor the evolutionary forces responsible for generating this diversity. One hypothesis is that trait diversity in the gall wasps, including the morphology of the galls they induce, has evolved in response to selection imposed by the parasitoid community, with reciprocal selection driving diversification of the parasitoids. Using a rare, continental‐scale data set of Sycophila parasitoid wasps reared from 44 species of cynipid galls from 18 species of oak across the USA, we combined mitochondrial DNA barcodes, ultraconserved elements (UCEs), morphological and natural history data to delimit putative species. Using these results, we generate the first large‐scale assessment of ecological specialization and host association in this species‐rich group, with implications for evolutionary ecology and biocontrol. We find most Sycophila target specific subsets of available cynipid host galls with similar morphologies, and generally attack larger galls. Our results suggest that parasitoid wasps such as Sycophila have adaptations allowing them to exploit particular host trait combinations, while hosts with contrasting traits are resistant to attack. These findings support the tritrophic niche concept for the structuring of plant–herbivore–parasitoid communities. [ABSTRACT FROM AUTHOR]
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- 2022
- Full Text
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45. The batched stepped wedge design: A design robust to delays in cluster recruitment.
- Author
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Kasza, Jessica, Bowden, Rhys, Hooper, Richard, and Forbes, Andrew B.
- Subjects
CLUSTER randomized controlled trials ,WEDGES - Abstract
Stepped wedge designs are an increasingly popular variant of longitudinal cluster randomized trial designs, and roll out interventions across clusters in a randomized, but step‐wise fashion. In the standard stepped wedge design, assumptions regarding the effect of time on outcomes may require that all clusters start and end trial participation at the same time. This would require ethics approvals and data collection procedures to be in place in all clusters before a stepped wedge trial can start in any cluster. Hence, although stepped wedge designs are useful for testing the impacts of many cluster‐based interventions on outcomes, there can be lengthy delays before a trial can commence. In this article, we introduce "batched" stepped wedge designs. Batched stepped wedge designs allow clusters to commence the study in batches, instead of all at once, allowing for staggered cluster recruitment. Like the stepped wedge, the batched stepped wedge rolls out the intervention to all clusters in a randomized and step‐wise fashion: a series of self‐contained stepped wedge designs. Provided that separate period effects are included for each batch, software for standard stepped wedge sample size calculations can be used. With this time parameterization, in many situations including when linear models are assumed, sample size calculations reduce to the setting of a single stepped wedge design with multiple clusters per sequence. In these situations, sample size calculations will not depend on the delays between the commencement of batches. Hence, the power of batched stepped wedge designs is robust to unexpected delays between batches. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
46. Speciation in Nearctic oak gall wasps is frequently correlated with changes in host plant, host organ, or both.
- Author
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Ward, Anna K. G., Bagley, Robin K., Egan, Scott P., Hood, Glen Ray, Ott, James R., Prior, Kirsten M., Sheikh, Sofia I., Weinersmith, Kelly L., Zhang, Linyi, Zhang, Y. Miles, and Forbes, Andrew A.
- Subjects
GALL wasps ,HOST plants ,REPRODUCTIVE isolation ,OAK ,PHYTOPHAGOUS insects ,GALL midges - Abstract
Quantifying the frequency of shifts to new host plants within diverse clades of specialist herbivorous insects is critically important to understand whether and how host shifts contribute to the origin of species. Oak gall wasps (Hymenoptera: Cynipidae: Cynipini) comprise a tribe of ∼1000 species of phytophagous insects that induce gall formation on various organs of trees in the family Fagacae—primarily the oaks (genus Quercus; ∼435 sp.). The association of oak gall wasps with oaks is ancient (∼50 my), and most oak species are galled by one or more gall wasp species. Despite the diversity of both gall wasp species and their plant associations, previous phylogenetic work has not identified the strong signal of host plant shifting among oak gall wasps that has been found in other phytophagous insect systems. However, most emphasis has been on the Western Palearctic and not the Nearctic where both oaks and oak gall wasps are considerably more species rich. We collected 86 species of Nearctic oak gall wasps from most of the major clades of Nearctic oaks and sequenced >1000 Ultraconserved Elements (UCEs) and flanking sequences to infer wasp phylogenies. We assessed the relationships of Nearctic gall wasps to one another and, by leveraging previously published UCE data, to the Palearctic fauna. We then used phylogenies to infer historical patterns of shifts among host tree species and tree organs. Our results indicate that oak gall wasps have moved between the Palearctic and Nearctic at least four times, that some Palearctic wasp clades have their proximate origin in the Nearctic, and that gall wasps have shifted within and between oak tree sections, subsections, and organs considerably more often than previous data have suggested. Given that host shifts have been demonstrated to drive reproductive isolation between host‐associated populations in other phytophagous insects, our analyses of Nearctic gall wasps suggest that host shifts are key drivers of speciation in this clade, especially in hotspots of oak diversity. Although formal assessment of this hypothesis requires further study, two putatively oligophagous gall wasp species in our dataset show signals of host‐associated genetic differentiation unconfounded by geographic distance, suggestive of barriers to gene flow associated with the use of alternative host plants. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
47. Towards higher-dimensional structured light.
- Author
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He, Chao, Shen, Yijie, and Forbes, Andrew
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- 2022
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48. Revealing the invariance of vectorial structured light in complex media.
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Nape, Isaac, Singh, Keshaan, Klug, Asher, Buono, Wagner, Rosales-Guzman, Carmelo, McWilliam, Amy, Franke-Arnold, Sonja, Kritzinger, Ané, Forbes, Patricia, Dudley, Angela, and Forbes, Andrew
- Abstract
Optical aberrations place fundamental limits on the achievable resolution with focusing and imaging. In the context of structured light, optical imperfections and misalignments and perturbing media such as turbulent air, underwater and optical fibre distort the amplitude and phase of the light's spatial pattern. Here we show that polarization inhomogeneity that defines vectorial structured light is immune to all such perturbations, provided they are unitary. As an example, we study the robustness of vector vortex beams propagating through highly aberrated systems, demonstrating that the inhomogeneous nature of polarization remains unaltered even as the medium itself changes. The unitary nature of the channel allows us to undo this change through a simple lossless operation. This approach paves the way to the versatile application of vectorial structured light, even through non-ideal optical systems, crucial in applications such as imaging and optical communication across noisy channels. Structured light is shown to be robust against unitary perturbations. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
49. Super-resolved quantum ghost imaging.
- Author
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Moodley, Chané and Forbes, Andrew
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HIGH resolution imaging ,GENERATIVE adversarial networks ,IMAGE reconstruction ,PHOTON flux - Abstract
Quantum ghost imaging offers many advantages over classical imaging, including low photon fluxes and non-degenerate object and image wavelengths for imaging light sensitive structures, but suffers from slow image reconstruction speeds. Image reconstruction times depend on the resolution of the required image which scale quadratically with the image resolution. Here, we propose a super-resolved imaging approach based on neural networks where we reconstruct a low resolution image, which we denoise and super-resolve to a high resolution image. To test the approach, we implemented both a generative adversarial network as well as a super-resolving autoencoder in conjunction with an experimental quantum ghost imaging setup, demonstrating its efficacy across a range of object and imaging projective mask types. We achieved super-resolving enhancement of 4 × the measured resolution with a fidelity close to 90 % at an acquisition time of N 2 measurements, required for a complete N × N pixel image solution. This significant resolution enhancement is a step closer to a common ghost imaging goal, to reconstruct images with the highest resolution and the shortest possible acquisition time. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
50. Causality of anthropometric markers associated with polycystic ovarian syndrome: Findings of a Mendelian randomization study.
- Author
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De Silva, Kushan, Demmer, Ryan T., Jönsson, Daniel, Mousa, Aya, Teede, Helena, Forbes, Andrew, and Enticott, Joanne
- Subjects
WAIST-hip ratio ,BODY mass index ,WAIST circumference ,BIOMARKERS ,SYNDROMES - Abstract
Introduction: Using body mass index (BMI) as a proxy, previous Mendelian randomization (MR) studies found total causal effects of general obesity on polycystic ovarian syndrome (PCOS). Hitherto, total and direct causal effects of general- and central obesity on PCOS have not been comprehensively analyzed. Objectives: To investigate the causality of central- and general obesity on PCOS using surrogate anthropometric markers. Methods: Summary GWAS data of female-only, large-sample cohorts of European ancestry were retrieved for anthropometric markers of central obesity (waist circumference (WC), hip circumference (HC), waist-to-hip ratio (WHR)) and general obesity (BMI and its constituent variables–weight and height), from the IEU Open GWAS Project. As the outcome, we acquired summary data from a large-sample GWAS (118870 samples; 642 cases and 118228 controls) within the FinnGen cohort. Total causal effects were assessed via univariable two-sample Mendelian randomization (2SMR). Genetic architectures underlying causal associations were explored. Direct causal effects were analyzed by multivariable MR modelling. Results: Instrumental variables demonstrated no weak instrument bias (F > 10). Four anthropometric exposures, namely, weight (2.69–77.05), BMI (OR: 2.90–4.06), WC (OR: 6.22–20.27), and HC (OR: 6.22–20.27) demonstrated total causal effects as per univariable 2SMR models. We uncovered shared and non-shared genetic architectures underlying causal associations. Direct causal effects of WC and HC on PCOS were revealed by two multivariable MR models containing exclusively the anthropometric markers of central obesity. Other multivariable MR models containing anthropometric markers of both central- and general obesity showed no direct causal effects on PCOS. Conclusions: Both and general- and central obesity yield total causal effects on PCOS. Findings also indicated potential direct causal effects of normal weight-central obesity and more complex causal mechanisms when both central- and general obesity are present. Results underscore the importance of addressing both central- and general obesity for optimizing PCOS care. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
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