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The transition to turbulence in Taylor–Couette flow often occurs via a sequence of supercritical bifurcations to progressively more complex, yet stable, flows. We describe a subcritical laminar–turbulent transition in the counter-rotating regime mediated by a transient intermediate state in a system with an axial aspect ratio of
and a radius ratio of
. In this regime, flow visualization experiments and numerical simulations indicate the intermediate state corresponds to an aperiodic flow featuring interpenetrating spirals. Furthermore, the reverse transition out of turbulence leads first to the same intermediate state, which is now stable, before returning to an azimuthally symmetric laminar flow. Time-resolved tomographic particle image velocimetry is used to characterize the experimental flows; these measurements compare favourably to direct numerical simulations with axial boundary conditions matching those of the experiments.
Traditional perspectives conceptualize resilience as a trait and depression as resulting from resilience deficiency. However, research indicates that resilience varies substantially even among adults who are clinically depressed, as well as across the lifespan of an individual. Few studies have investigated resilience in depression, and even fewer have examined resilience in depressed older adults.
Three hundred thirty-seven adults ≥60 years with major depressive disorder completed the Connor–Davidson Resilience Scale (CD-RISC) and measures of mental health, quality of life (QOL), and medical comorbidity. Exploratory factor analysis was used to explore the factor structure of the CD-RISC. Correlations and general linear models were used to examine associations between resilience and other variables.
The rotated component matrix indicated a four-factor model. Sorting of items by highest factor loading revealed constructs associated with (1) grit, (2) active coping self-efficacy, (3) accommodative coping self-efficacy, and (4) spirituality. Resilience was significantly correlated with increased age, lower cognitive functioning, greater cerebrovascular risk, and greater medical comorbidity. Resilience was negatively associated with mental health symptoms (depression, apathy, and anxiety) and positively associated with QOL. The final optimal model identified less depression, less apathy, greater medical comorbidity, higher QOL, and minority (non-White) race as factors that significantly explained variability in resilience.
Resilience was significantly associated with a range of mental health constructs in a sample of older adults with depression. Future clinical trials and dismantling studies may help determine whether interventions targeting grit, active coping, accommodative coping, and spirituality can increase resilience and help prevent and treat depression in older adults.
The Accountability for Reasonableness (A4R) framework addresses the legitimacy of coverage decision processes by defining four conditions for accountable and reasonable processes: Relevance, Publicity, Appeals, Implementation. Cost-per-quality-adjusted life year (QALY) and multicriteria-centered processes may have distinct implications for meeting A4R conditions. The aim of this study was to reflect on how the diverse features of decision-making processes can be aligned with A4R conditions to guide legitimized decision-making. Rare disease and regenerative therapies (RDRTs) pose special decision-making challenges and offer a useful case study.
To support reflection on how different approaches address the A4R conditions, thirty-four features operationalizing each condition were defined and organized into a matrix. Seven experts from six countries explored and discussed these features during a panel (Chatham House Rule) and provided general and RDRT-specific recommendations for each feature. Responses were analyzed to identify converging and diverging recommendations.
Regarding Relevance, panelists highlighted the importance of supporting deliberation, stakeholder participation and grounding coverage decision criteria in the legal framework, goals of sustainable healthcare and population values. Among seventeen criteria, thirteen were recommended by more than half of panelists. Although the cost-effectiveness ratio was deemed sometimes useful, the validity of universal thresholds to inform allocative efficiency was challenged. Regarding Publicity, panelists recommended communicating the values underlying a decision in reference to broader societal objectives, and being transparent about value judgements in selecting evidence. For Appeals, recommendations included clear definition of new evidence and revision rules. For Implementation, one recommendation was to perform external quality reviews of decisions. While RDRTs raise issues that may warrant special consideration, rarity should be considered in interaction with other aspects (e.g. disease severity, age, budget impact).
Improving coverage decision-making towards accountability and reasonableness involves supporting participation and deliberation, enhancing transparency, and more explicit consideration of multiple decision criteria that reflect normative and societal objectives.
We present a combined experimental and theoretical study of the primary and secondary instabilities in a Kolmogorov-like flow. The experiment uses electromagnetic forcing with an approximately sinusoidal spatial profile to drive a quasi-two-dimensional (Q2D) shear flow in a thin layer of electrolyte suspended on a thin lubricating layer of a dielectric fluid. Theoretical analysis is based on a two-dimensional (2D) model (Suri et al., Phys. Fluids, vol. 26 (5), 2014, 053601), derived from first principles by depth-averaging the full three-dimensional Navier–Stokes equations. As the strength of the forcing is increased, the Q2D flow in the experiment undergoes a series of bifurcations, which is compared with results from direct numerical simulations of the 2D model. The effects of confinement and the forcing profile are studied by performing simulations that assume spatial periodicity and strictly sinusoidal forcing, as well as simulations with realistic no-slip boundary conditions and an experimentally validated forcing profile. We find that only the simulation subject to physical no-slip boundary conditions and a realistic forcing profile provides close, quantitative agreement with the experiment. Our analysis offers additional validation of the 2D model as well as a demonstration of the importance of properly modelling the forcing and boundary conditions.
Active Trypanosoma cruzi transmission persists in the Gran Chaco region, which is considered hyperendemic for Chagas disease. Understanding domestic and sylvatic transmission cycles and therefore the relationship between vectors and mammalian hosts is crucial to designing and implementing improved effective control strategies. Here we describe the species of triatomine vectors and the sylvatic mammal reservoirs of T. cruzi, in different localities of the Paraguayan and Bolivian Chaco. We identify the T. cruzi genotypes discrete typing units (DTUs) and provide a map of their geographical distribution. A total of 1044 triatomines and 138 sylvatic mammals were captured. Five per cent of the triatomines were microscopically positive for T. cruzi (55 Triatoma infestans from Paraguay and one sylvatic Triatoma guasayana from Bolivia) and 17 animals (12·3%) comprising eight of 28 (28·5%) Dasypus novemcinctus, four of 27 (14·8%) Euphractus sexcinctus, three of 64 (4·7%) Chaetophractus spp. and two of 14 (14·3%) Didelphis albiventris. The most common DTU infecting domestic triatomine bugs was TcV (64%), followed by TcVI (28%), TcII (6·5%) and TcIII (1·5%). TcIII was overwhelmingly associated with armadillo species. We confirm the primary role of T. infestans in domestic transmission, armadillo species as the principal sylvatic hosts of TcIII, and consider the potential risk of TcIII as an agent of Chagas disease in the Chaco.
This paper describes the digitization and enrichment of the Canadian House of Commons English Debates from 1901 to present. We start by laying out the general framework in which this project took place and then present the structure of the database and provide guidelines to prospective users. The paper concludes with the introduction of www.lipad.ca, an online platform designed as a hub for archiving Canadian political data, with the parliamentary proceedings at the centre of its architecture.
In the era of multi-modality imaging, this study compared contemporary, pre-operative echocardiography and cardiac MRI in predicting the need for intervention on additional lesions before surgical bidirectional cavopulmonary connection.
A total of 72 patients undergoing bidirectional cavopulmonary connection for single-ventricle palliation between 2007 and 2012, who underwent pre-operative assessment using both echocardiography and MRI, were included. The pre-determined outcome measure was any additional surgical or catheter-based intervention within 6 months of bidirectional cavopulmonary connection. Indices assessed were as follows: indexed dimensions of right and left pulmonary arteries, coarctation of the aorta, adequacy of interatrial communication, and degree of atrioventricular valve regurgitation.
Median age at bidirectional cavopulmonary connection was 160 days (interquartile range 121–284). The following MRI parameters predicted intervention: Z score for right pulmonary artery (odds ratio 1.77 (95% confidence interval 1.12–2.79, p=0.014)) and left pulmonary artery dimensions (odds ratio 1.45 (1.04–2.00, p=0.027)) and left pulmonary artery report conclusion (odds ratio 1.57 (1.06–2.33)). The magnetic resonance report predicted aortic arch intervention (odds ratio 11.5 (3.5–37.7, p=0.00006)). The need for atrioventricular valve repair was associated only with magnetic resonance regurgitation fraction score (odds ratio 22.4 (1.7–295.1, p=0.018)). Echocardiography assessment was superior to MRI for predicting intervention on interatrial septum (odds ratio 27.7 (6.3–121.6, p=0.00001)).
For branch pulmonary arteries, aortic arch, and atrioventricular valve regurgitation, MRI parameters more reliably predict the need for intervention; however, echocardiography more accurately identified the adequacy of interatrial communication. Approaching bidirectional cavopulmonary connection, the diagnostic strengths of MRI and echocardiography should be acknowledged when considering intervention.
We report on the analysis of virtual powder-diffraction patterns from serial femtosecond crystallography (SFX) data collected at an X-ray free-electron laser. Different approaches to binning and normalizing these patterns are discussed with respect to the microstructural characteristics which each highlights. Analysis of SFX data from a powder of Pr0.5Ca0.5MnO3 in this way finds evidence of other trace phases in its microstructure which was not detectable in a standard powder-diffraction measurement. Furthermore, a comparison between two virtual powder pattern integration strategies is shown to yield different diffraction peak broadening, indicating sensitivity to different types of microstrain. This paper is a first step in developing new data analysis methods for microstructure characterization from serial crystallography data.
Tabling has been used for some time to improve efficiency of Prolog programs by memorizing answered queries. The same idea can be naturally used to memorize visited states during search for planning. In this paper we present a planner developed in the Picat language to solve the Petrobras planning problem. Picat is a novel Prolog-like language that provides pattern matching, deterministic and non-deterministic rules, and tabling as its core modelling and solving features. We demonstrate these capabilities using the Petrobras problem, where the goal is to plan transport of cargo items from ports to platforms using vessels with limited capacity. Monte Carlo Tree Search has been so far the best technique to tackle this problem and we will show that by using tabling we can achieve much better runtime efficiency and better plan quality.