Magnetically soft, high moment grain-refined Fe films: application to magnetic tunnel junctions

The effect of N-doping on the microstructure and magnetic properties of thin Fe layers has been employed to construct all Fe-electrode magnetic tunnel junctions that displayed the tunneling magnetoresistance (TMR) effect. Using low nitrogen doses, a reduction in coercivity was achieved due to grain refinement, without a concurrent decrease in the saturation magnetization of the Fe films caused by the formation of crystalline iron nitride phases. It was demonstrated that this N-induced grain refinement can be applied beneficially to control the switching field of the "free" layer in magnetic trilayer structures. In general the ability to control magnetic softness without reducing saturation magnetization will prove important for incorporating high spin-polarized materials into spin valves and TMR devices

Scaling of the geomagnetic secular variation timescale

\ua9 2024 The Author(s).The ratio of the magnetic power spectrum and the secular variation spectrum measured at the Earth\u27s surface provides a timescale as a function of spherical harmonic degree l. is often assumed to be representative of timescales related to the dynamo inside the outer core and its scaling with l is debated. To assess the validity of this surmise and to study the time variation of the geomagnetic field inside the outer core, we introduce a magnetic timescale spectrum that is valid for all radius r above the inner core and reduces to the usual at and above the core-mantle boundary (CMB). We study in a numerical geodynamo model. At the CMB, we find that is valid at both the large and small scales, in agreement with previous numerical studies on. Just below the CMB, the scaling undergoes a sharp transition at small l. Consequently, in the interior of the outer core, exhibits different scaling at the large and small scales, specifically, the scaling of becomes shallower than at small l. We find that this transition at the large scales stems from the fact that the horizontal components of the magnetic field evolve faster than the radial component in the interior. In contrast, the magnetic field at the CMB must match onto a potential field, hence the dynamics of the radial and horizontal magnetic fields are tied together. The upshot is becomes unreliable in estimating timescales inside the outer core. Another question concerning is whether an argument based on the frozen-flux hypothesis can be used to explain its scaling. To investigate this, we analyse the induction equation in the spectral space. We find that away from both boundaries, the magnetic diffusion term is negligible in the power spectrum of. However, is controlled by the radial derivative in the induction term, thus invalidating the frozen-flux argument. Near the CMB, magnetic diffusion starts to affect rendering the frozen-flux hypothesis inapplicable. We also examine the effects of different velocity boundary conditions and find that the above results apply for both no-slip and stress-free conditions at the CMB

Characterising Jupiter's dynamo radius using its magnetic energy spectrum

Jupiter's magnetic field is generated by the convection of liquid metallic hydrogen in its interior. The transition from molecular hydrogen to metallic hydrogen as temperature and pressure increase is believed to be a smooth one. As a result, the electrical conductivity in Jupiter varies continuously from being negligible at the surface to a large value in the deeper region. Thus, unlike the Earth where the upper boundary of the dynamo—the dynamo radius—is definitively located at the core-mantle boundary, it is not clear at what depth dynamo action becomes significant in Jupiter. In this paper, using a numerical model of the Jovian dynamo, we examine the magnetic energy spectrum at different depth and identify a dynamo radius below which (and away from the deep inner core) the shape of the magnetic energy spectrum becomes invariant. We find that this shift in the behaviour of the magnetic energy spectrum signifies a change in the dynamics of the system as electric current becomes important. Traditionally, a characteristic radius derived from the Lowes–Mauersberger spectrum—the Lowes radius—gives a good estimate to the Earth's core-mantle boundary. We argue that in our model, the Lowes radius provides a lower bound to the dynamo radius. We also compare the Lowes–Mauersberger spectrum in our model to that obtained from recent Juno observations. The Lowes radius derived from the Juno data is significantly lower than that obtained from our models. The existence of a stably stratified region in the neighbourhood of the transition zone might provide an explanation of this result

Monitoring and improving the quality of person-centred care in health and social settings using Dementia Care Mapping (DCM): Staff experiences of implementation barriers and supports

Dementia Care Mapping (DCM) is a person-centred care quality monitoring and improvement tool used for nearly 20 years in formal dementia care settings and there are thousands of people trained in its use internationally. However, little is known about if and how DCM is used in practice or regarding application of inter-rater reliability checks to ensure data quality. This study aimed to explore the application of DCM in practice in the UK. A mixed methods design including an on-line survey and in-depth, semi-structured interviews was employed. There were 98 survey respondents, representing 71 health and social care, University/research and training/consultancy organisations. Twenty-one people participated in the semi-structured interviews. Fifty-nine percent of survey respondents had used DCM since completing training. Those working in clinical roles and in health and social care provider organisations were least likely to have used DCM. A range of barriers and supports to use of DCM in practice after training were reported, including lack of management support and time. The majority of those who had used DCM also conducted inter-rater reliability checks at least once per year or more frequently. Of the 20% who did not the main barriers to this were absence of someone to conduct the checks with and lack of time and resources. The study has shown that it is possible to apply an evidence-based quality monitoring and improvement tool such as DCM to support implementation of person-centred care in practice, despite widespread limitations on time and resources as well as identifying a range of setting conditions that can help or hinder implementation

The dynamics of magnetic Rossby waves in spherical dynamo simulations: A signature of strong-field dynamos?

We investigate slow magnetic Rossby waves in convection-driven dynamos in rotating spherical shells. Quasi-geostrophic waves riding on a mean zonal flow may account for some of the geomagnetic westward drifts and have the potential to allow the toroidal field strength within the planetary fluid core to be estimated. We extend the work of Hori et al. (2015) to include a wider range of models, and perform a detailed analysis of the results. We find that a predicted dispersion relation matches well with the longitudinal drifts observed in our strong-field dynamos. We discuss the validity of our linear theory, since we also find that the nonlinear Lorentz terms influence the observed waveforms. These wave motions are excited by convective instability, which determines the preferred azimuthal wavenumbers. Studies of linear rotating magnetoconvection have suggested that slow magnetic Rossby modes emerge in the magnetostrophic regime, in which the Lorentz and Coriolis forces are in balance in the vorticity equation. We confirm this to be predominant balance for the slow waves we have detected in nonlinear dynamo systems. We also show that a completely different wave regime emerges if the magnetic field is not present. Finally we report the corresponding radial magnetic field variations observed at the surface of the shell in our simulations and discuss the detectability of these waves in the geomagnetic secular variation

Viscous and inviscid strato-rotational instability

We examine the critical viscous mode of the Taylor–Couette strato-rotational instability, concentrating on cases where the buoyancy frequency N and the inner cylinder rotation rate Ωin are comparable, giving a detailed account for N = Ωin. The ratio of the outer to the inner cylinder rotation rates µ = Ωout/Ωin and the ratio of the inner to the outer cylinder radius η = rin/rout satisfy 0 < µ < 1 and 0 < η < 1. We find considerable variation in the structure of the mode, and the critical Reynolds number Rec at which the flow becomes unstable. For N = Ωin, we classify different regions of the ηµ-plane by the critical viscous mode of each region. We find that there is a triple point in the ηµ-plane where three different viscous modes all onset at the same Reynolds number. We also find a discontinuous change in Rec along a curve in the ηµ-plane, on one side of which exist closed unstable domains where the flow can restabilise when the Reynolds number is increased. A new form of viscous instability occurring for wide gaps has been detected. We show for the first time that there is a region of the parameter space for which the critical viscous mode at the onset of instability corresponds to the inviscid radiative instability of Le Dizès & Riedinger (J. Fluid Mech., vol. 660, 2010, pp. 147–161). Focusing on small-to-moderate wavenumbers, we demonstrate that the viscous and inviscid systems are not always correlated. We explore which viscous modes relate to inviscid modes and which do not. For asymptotically large vertical wavenumbers, we have extended the inviscid analysis of Park & Billant (J. Fluid Mech., vol. 725, 2013, pp. 262–280) to cover the cases where N and Ωin are comparable

Convective turbulent viscosity acting on equilibrium tidal flows: new frequency scaling of the effective viscosity

Turbulent convection is thought to act as an effective viscosity (νE) in damping tidal flows in stars and giant planets. However, the efficiency of this mechanism has long been debated, particularly in the regime of fast tides, when the tidal frequency (ω) exceeds the turnover frequency of the dominant convective eddies (ωc). We present the results of hydrodynamical simulations to study the interaction between tidal flows and convection in a small patch of a convection zone. These simulations build upon our prior work by simulating more turbulent convection in larger horizontal boxes, and here we explore a wider range of parameters. We obtain several new results: (1) νE is frequency dependent, scaling as ω−0.5 when ω/ωc ≲ 1, and appears to attain its maximum constant value only for very small frequencies (ω/ωc ≲ 10−2). This frequency reduction for low-frequency tidal forcing has never been observed previously. (2) The frequency dependence of νE appears to follow the same scaling as the frequency spectrum of the energy (or Reynolds stress) for low and intermediate frequencies. (3) For high frequencies (ω/ωc ≳ 1 − 5), νE ∝ ω−2. 4) The energetically dominant convective modes always appear to contribute the most to νE, rather than the resonant eddies in a Kolmogorov cascade. These results have important implications for tidal dissipation in convection zones of stars and planets, and indicate that the classical tidal theory of the equilibrium tide in stars and giant planets should be revisited. We briefly touch upon the implications for planetary orbital decay around evolving stars

Health information needs, source preferences and engagement behaviours of women with metastatic breast cancer across the care continuum: protocol for a scoping review

INTRODUCTION: The health information needs, information source preferences and engagement behaviours of women with metastatic breast cancer (mBC) depend on personal characteristics such as education level, prior knowledge, clinical complications, comorbidities and where they are in the cancer journey. A thorough understanding of the information behaviours of women living with mBC is essential to the provision of optimal care. A preliminary literature review suggests that there is little research on this topic, but that there may be lessons from a slightly broader literature. This review will identify what is known and what is not known about the health information needs, acquisition and influences of women with mBC across the care continuum. Findings will help to identify research needs and specific areas where in-depth systematic reviews may be feasible, as well as inform evidence-based interventions to address the health information needs of female patients with mBC with different demographics and characteristics and across the mBC journey. METHODS AND ANALYSIS: A scoping review will be performed using the guidelines of Arksey and O'Malley as updated by subsequent authors to systematically search scientific and grey literature for articles in English that discuss the health information needs, source preferences, engagement styles, and associated personal and medical attributes of women ≥18 years living with mBC at different stages of the disease course. A variety of databases (including Cumulative Index to Nursing and Allied Health Literature (CINAHL), PubMed, Excerpta Medica Database (EMBASE), Academic Search Premier, Cochrane Database of Systematic Reviews, PsycINFO, Health Source: Nursing/Academic Edition, and PQDT Open), oncology, patient advocacy and governmental websites will be searched from inception to present day. Research and non-research literature will be included; no study designs will be excluded. The six-stage Arksey and O'Malley scoping review methodological framework involves: (1) identifying the research question; (2) searching for relevant studies; (3) selecting studies; (4) charting the data; (5) collating, summarising and reporting the results; and (6) consulting with stakeholders to inform or validate study findings (optional). Data will be extracted and analysed using a thematic chart and descriptive content analysis. ETHICS AND DISSEMINATION: Being a secondary analysis, this research will not require ethics approval. Results will be disseminated through patient support organisations and websites and publications targeting healthcare professionals, advocates and patients

From campus to communities: evaluation of the first UK-based bystander programme for the prevention of domestic violence and abuse in general communities

This is the final version. Available from the publisher via the DOI in this record.The datasets used during the current study are available from the corresponding author under reasonable request.BACKGROUND: Violence against women and girls is a public health epidemic. Campus-based research has found bystander programmes show promise as effective primary prevention of sexual violence. However, evidence regarding domestic violence and abuse bystander prevention specifically, and in community settings generally, is still in development. Further, research has predominantly emanated from the US. Examining proof of concept in differing cultural contexts is required. This study evaluates the feasibility and potential for effectiveness of a domestic violence and abuse bystander intervention within UK general communities-Active Bystander Communities. METHODS: Participants recruited opportunistically attended a three-session programme facilitated by experts in the field. Programme feasibility was measured using participant attendance and feedback across nine learning objectives. Myth acceptance, bystander efficacy, behavioural intent and bystander behaviours were assessed using validated scales at baseline, post-intervention, and four-month follow-up. Results were examined for potential backlash. Analyses used a paired sample t-test and effect size was quantified with Cohen's d. RESULTS: 58/70 participants attended all programme sessions. Participant feedback consistently rated the programme highly and significant change (p ≤ 0·001) was observed in the desired direction across behavioural intent, bystander efficacy, and myth acceptance scores at post and follow-up. Effect size was generally large and, with the exception of Perception of Peer Myth Acceptance, improved at follow-up. Backlash was minimal. CONCLUSIONS: To our knowledge this is the first UK-based study to examine the potential of bystander intervention as a community-level intervention for domestic violence and abuse. Findings are promising and indicate the translatability of the bystander approach to domestic violence and abuse prevention as well as community contexts. This is likely to be of great interest to policymakers and may help shape future community-based interventions. Further research is now needed using experimental designs engaging diverse community audiences.Bristol City Counci

Angular momentum transport, layering, and zonal jet formation by the GSF instability: non-linear simulations at a general latitude

We continue our investigation into the non-linear evolution of the Goldreich–Schubert–Fricke (GSF) instability in differentially rotating radiation zones. This instability may be a key player in transporting angular momentum in stars and giant planets, but its non-linear evolution remains mostly unexplored. In a previous paper we considered the equatorial instability, whereas here we simulate the instability at a general latitude for the first time. We adopt a local Cartesian Boussinesq model in a modified shearing box for most of our simulations, but we also perform some simulations with stress-free, impenetrable, radial boundaries. We first revisit the linear instability and derive some new results, before studying its non-linear evolution. The instability is found to behave very differently compared with its behaviour at the equator. In particular, here we observe the development of strong zonal jets (‘layering’ in the angular momentum), which can considerably enhance angular momentum transport, particularly in axisymmetric simulations. The jets are, in general, tilted with respect to the local gravity by an angle that corresponds initially with that of the linear modes, but which evolves with time and depends on the strength of the flow. The instability transports angular momentum much more efficiently (by several orders of magnitude) than it does at the equator, and we estimate that the GSF instability could contribute to the missing angular momentum transport required in both red giant and subgiant stars. It could also play a role in the long-term evolution of the solar tachocline and the atmospheric dynamics of hot Jupiters