114612 research outputs found
Sort by
Theory of defect-induced crystal field perturbations in rare-earth magnets
Get PDFWe present a theory describing the single-ion anisotropy of rare-earth (RE) magnets in the presence of point defects. Taking the RE-lean 1∶12 magnet class as a prototype, we use first-principles calculations to show how the introduction of Ti substitutions into SmFe_{12} perturbs the crystal field, generating new coefficients due to the lower symmetry of the RE environment. We then demonstrate that these perturbations can be described extremely efficiently using a screened point charge model. We provide analytical expressions for the anisotropy energy that can be straightforwardly implemented in atomistic spin dynamics simulations, meaning that such simulations can be carried out for an arbitrary arrangement of point defects. The significant crystal field perturbations calculated here demonstrate that a sample that is single phase from a structural point of view can nonetheless have a dramatically varying anisotropy profile at the atomistic level if there is compositional disorder, which may influence localized magnetic objects like domain walls or skyrmions
Applications of nanomaterial technology in biosensing
Get PDFNanomaterial technology is a comprehensive subject with strong intersections, and its related research content involves a wide range of modern scientific and technological fields. The science and technology in the area of of nanomaterials has attracted the attention of many research groups over the past few years. By its very nature, this topic has a lot of room for research, related to very tiny objects in the nanometer range. Nanomaterials refer to the sudden changes in the properties of substances when they reach the nanometer scale, resulting in special properties. In this paper, we introduce various nanomaterials commonly used in the field of biosensing, and briefly explain the advantages and disadvantages of nanoscale biosensors. At the same time, we also explain the working principles of various types of biosensors based on nanomaterial technology, including electrochemical biosensors, optical biosensors, and piezoelectric biosensors. In addition, we also introduce the sensing targets of common biosensors, such as enzymes, DNA, microorganisms, etc. Finally, we discuss the challenges and prospects for the application of nanomaterials technology in biosensing, and analyze the current trends and future directions
Bayesian optimisation for quality diversity search with coupled descriptor functions
Get PDFQuality Diversity (QD) algorithms such as the Multi- Dimensional Archive of Phenotypic Elites (MAP-Elites) are a class of optimisation techniques that attempt to find many high performing points that all behave differently according to a userdefined behavioural metric. In this paper we propose the Bayesian Optimisation of Elites (BOP-Elites) algorithm. Designed for problems with expensive fitness functions and coupled behaviour descriptors, it is able to return a QD solution-set with excellent performance already after a relatively small number of samples. BOP-Elites models both fitness and behavioural descriptors with Gaussian Process surrogate models and uses Bayesian Optimisation strategies for choosing points to evaluate in order to solve the quality-diversity problem. In addition, BOP-Elites produces high quality surrogate models which can be used after convergence to predict solutions with any behaviour in a continuous range. An empirical comparison shows that BOP-Elites significantly outperforms other state-of-the-art algorithms without the need for problem-specific parameter tuning
Prehospital optimal shock energy for defibrillation (POSED) : a cluster randomised controlled feasibility trial
Get PDFWe explored the feasibility of a large-scale UK ambulance services trial of optimal defibrillation shock energy for out-of-hospital cardiac arrest. The primary objective of this feasibility study was to establish the number of eligible patients and the number recruited. Secondary outcomes were adherence to allocated treatment and data completeness. We conducted a three-arm parallel group cluster randomised controlled feasibility study in a single ambulance service in southern England. Adult patients in out-of-hospital cardiac arrest treated for a shockable rhythm were included. Zoll X series defibrillators (clusters) were randomised to deliver 120-150-200 J, 150-200-200 J, or 200-200-200 J shock strategies. Between March 2022 and February 2023, we randomised 38 eligible patients (120-150-200 J (n = 12), 150-200-200 J (n = 10), 200-200-200 J (n = 16)) to the study. The recruitment rate per cluster was 0.07 per month. The median patient age was 71 years (IQR 59-81 years); 79% were male. Twenty-eight cardiac arrests (74%) occurred in a private residence, 29 (76%) were witnessed and 32 (84%) patients received bystander CPR. Treatment adherence was 93% and completeness of clinical and electrical outcomes was 86%. At 30 days, 3/36 (8.3%) patients survived; we were unable to collect survival outcomes for two patients. Defibrillation data collection became difficult when defibrillators became separated from their allocated vehicles. We have demonstrated the feasibility of a cluster randomised controlled trial of optimal shock energy for defibrillation in a UK ambulance service. We have identified possible solutions to issues relating to trial design. [Abstract copyright: © 2024 The Author(s).
‘See sincerity sparkle in thy practice' : antidotes to hypocrisy in British print sermons, 1640–1695
No full textSeventeenth-century British preachers persistently defined hypocrisy in contrast to its divine antidote: sincerity. This article looks at four such case studies from across the ‘puritan’-‘Anglican’ divide, analysing the sermons of the Independent Nicholas Lockyer, the Presbyterian Christopher Love, the Church of England clergyman James Oldfield, and the archbishop of Canterbury John Tillotson. It considers to what extent Protestant instruction on sincerity and hypocrisy shifted according to religious affiliation and socio-political context, arguing that although these sermons possessed considerable continuities in their theological underpinnings, they also exhibited divergences in focus and instruction that are sometimes, but not always, predictable along denominational lines. These differences held weighty implications for the individual receiving spiritual guidance on how to forswear hypocrisy and live a truly sincere life, particularly throughout the period of instability and contention that marked Britain from the Civil Wars to the Glorious Revolution
Real-time adaptive estimation of decoherence timescales for a single qubit
Get PDFCharacterizing the time over which quantum coherence survives is critical for any implementation of quantum bits, memories, and sensors. The usual method for determining a quantum system’s decoherence rate involves a suite of experiments probing the entire expected range of this parameter, and extracting the resulting estimation in postprocessing. Here we present an adaptive multiparameter Bayesian approach, based on a simple analytical update rule, to estimate the key decoherence timescales (T1, T
∗2, and T2) and the corresponding decay exponent of a quantum system in real time, using information gained in preceding experiments. This approach reduces the time required to reach a given uncertainty by a factor up to an order of magnitude, depending on the specific experiment, compared to the standard protocol of curve fitting. A further speedup of a factor approximately 2 can be realized by performing our optimization with respect to sensitivity as opposed to varianc
The TESS-SPOC FFI target sample explored with gaia
Get PDFThe Transiting Exoplanet Survey Satellite (TESS) mission has provided the community with high-precision times-series photometry for ∼2.8 million stars across the entire sky via the full frame image (FFI) light curves produced by the TESS Science Processing Operations Center (SPOC). This set of light curves is an extremely valuable resource for the discovery of transiting exoplanets and other stellar science. However, due to the sample selection, this set of light curves does not constitute a magnitude-limited sample. In order to understand the effects of this sample selection, we use Gaia Data Release 2 (DR2) and Data Release 3 (DR3) to study the properties of the stars in the TESS-SPOC FFI light-curve set, with the aim of providing vital context for further research using the sample. We report on the properties of the TESS-SPOC FFI targets in Sectors 1–55 (covering Cycles 1–4). We cross-match the TESS-SPOC FFI targets with the Gaia DR2 and DR3 catalogues of all targets brighter than Gaia magnitude 14 to understand the effects of sample selection on the overall stellar properties. This includes Gaia magnitude, parallax, radius, temperature, non-single star flags, luminosity, radial velocity, and stellar surface gravity. In total, there are ∼16.7 million Gaia targets brighter than G = 14, which when cross-matched with the TESS-SPOC FFI targets leaves ∼2.75 million. We investigate the binarity of each TESS-SPOC FFI target and calculate the radius detection limit from two detected TESS transits that could be detected around each target. Finally, we create a comprehensive main-sequence TESS-SPOC FFI target sample that can be utilized in future studies
TESS duotransit candidates from the Southern Ecliptic Hemisphere
Get PDFDiscovering transiting exoplanets with long orbital periods allows us to study warm and cool planetary systems with temperatures similar to the planets in our own Solar system. The Transiting Exoplanet Survey Satellite (TESS) mission has photometrically surveyed the entire Southern Ecliptic Hemisphere in Cycle 1 (2018 August–2019 July), Cycle 3 (2020 July–2021 June), and Cycle 5 (2022 September–2023 September). We use the observations from Cycle 1 and Cycle 3 to search for exoplanet systems that show a single transit event in each year, which we call duotransits. The periods of these planet candidates are typically in excess of 20 d, with the lower limit determined by the duration of individual TESS observations. We find 85 duotransit candidates, which span a range of host star brightnesses: 8 < Tmag < 14, transit depths between 0.1 per cent and 1.8 per cent, and transit durations between 2 and 10 h with the upper limit determined by our normalization function. Of these candidates, 25 are already known, and 60 are new. We present these candidates along with the status of photometric and spectroscopic follow-up
Advanced equivalent consumption minimization strategy for fuel cell hybrid electric vehicles
No full textThis paper aims to develop an Advanced Equivalent Consumption Minimization Strategy (AECMS) for efficient fuel cell hybrid electric vehicles (FCHEV). The Equivalent Consumption Minimization Strategy (ECMS) is one of the most feasible solutions for hybrid electric vehicles as it has less complexity and low computational cost in making the optimal control decision. However, typical ECMS designs with fixed gain use could not enhance an optimal energy control when dealing with multi decisive factors for highly non-linear and uncertain systems like FCHEVs. To address this control challenge, the AECMS is developed as the combination of the ECMS and an adaptive equivalence factor to optimally split the energy flow between the fuel cell and battery in the FCHEV. First, a cost function is formulated based on two key objectives which are power consumptions of the fuel cell and battery, the equivalence factor and a set of soft and hard constraints, considering the number of fuel cell start/stop, fuel cell optimal operating range, state of charge (SoC) range, temperature ranges and power limits. Second, the adaptive equivalence factor is newly designed as the combination of states and dynamics of the fuel cell and battery and corresponding weighting factors. Third, fuzzy inferences are derived to adjust online the weighting factors in an adaptive manner according to the working conditions of the energy sources, subsequently improving the overall vehicle energy efficiency and maintaining the battery SoC while prolonging their lifetime. Numerical simulations using a FCHEV model have been carried out under UDDS and HWFET drive cycles to illustrate the superior performance of the AECMS against the traditional ECMS
‘It’s so Beneficial to be Able to Stop the Cycle’ : perceptions of intergenerational transmission of violence and parenting practices among pregnant women and their abusive partners
Get PDFPurpose:
This study aimed to explore how pregnant women who experience Domestic Violence and Abuse (DVA) and men who commit DVA understand the impact of their childhood environment on their relationships with their children and co-parents, and how a DVA psychological intervention may shape their parenting.
Methods:
Repeated individual qualitative interviews were conducted with pregnant mothers and fathers who reported DVA and were taking part in a psychological intervention to address DVA. Interviews were carried out at the start (during pregnancy) and end of the intervention (two years post-childbirth). Reflexive Thematic Analysis was used to analyse interviews.
Results:
56 interviews (26 mothers; 13 fathers) were analysed. Five themes were identified: (1) Acknowledging childhood experiences of DVA; (2) The scars of traumatic experiences; (3) Challenging the silencing of abuse; (4) The transmission of parenting styles and behaviours from one generation to another; (5) Becoming the best parent one can be. The intergenerational transmission of violence was identifiable in most narratives. Despite this, several participants described skills they acquired during the intervention (e.g., emotional regulation strategies) as assisting in interrupting violence and improving their relationships with their children.
Conclusions:
Participants who acknowledged having encountered childhood abuse recognised it as one of several risk factors for DVA in adulthood. They also discussed the potential for trauma-informed interventions to address the intergenerational transmission of violence and poor parenting practices