219 research outputs found

    Spin and orbital moments of ultra-thin Fe films on various semiconductor surfaces

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    The magnetic moments of ultrathin Fe films on three different III-V semiconductor substrates, namely GaAs, InAs and In0.2Ga0.8As have been measured with X-ray magnetic circular dichroism at room temperature to assess their relative merits as combinations suitable for next-generation spintronic devices. The results revealed rather similar spin moments and orbital moments for the three systems, suggesting the relationship between film and semiconductor lattice parameters to be less critical to magnetic moments than magnetic anisotropy

    Interface alloying effects in the magnetic properties of Fe nanoislands capped with different materials

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    We show that Fe nanoislands capped with Al, Pd, and Pt protecting layers include an alloy at the interface with the capping layer, which explains the previously known capping layer dependence on the interparticle magnetic coupling. Vibrating sample magnetometry results, for instance, are evidencing a reduction in the magnetization measured under a magnetic field of 15 mT, which is larger in the case of the Al capping and which is due to the presence of a magnetically dead interface alloy. This reduction is also observed at the atomic level using x-ray magnetic circular dichroism measurements, showing a capping layer dependence of the Fe magnetic-moment reduction that is similar for the Pd and Pt capping, and stronger for the Al capping. The trend in the magnetic properties as a function of the capping layer is explained in the light of x-ray photoemission spectroscopy results that evidence the formation of alloys at the interface between the Fe nanoislands and the capping layers. The present results highlight the strong influence of interface alloying in systems of reduced dimensionality. In particular, it is shown that the magnetic properties are strongly affected at both the atomic and macroscopic level

    Reporting quality of published reviews of commercial and publicly available mobile health apps (mHealth app reviews): A scoping review protocol

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    \ua9 Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY. Published by BMJ.Introduction Reviews of commercial and publicly available smartphone (mobile) health applications (mHealth app reviews) are being undertaken and published. However, there is variation in the conduct and reporting of mHealth app reviews, with no existing reporting guidelines. Building on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we aim to develop the Consensus for APP Review Reporting Items (CAPPRRI) guidance, to support the conduct and reporting of mHealth app reviews. This scoping review of published mHealth app reviews will explore their alignment, deviation, and modification to the PRISMA 2020 items for systematic reviews and identify a list of possible items to include in CAPPRRI. Method and analysis We are following the Joanna Briggs Institute approach and Arksey and O\u27Malley\u27s five-step process. Patient and public contributors, mHealth app review, digital health research and evidence synthesis experts, healthcare professionals and a specialist librarian gave feedback on the methods. We will search SCOPUS, CINAHL Plus, AMED, EMBASE, Medline, APA PsycINFO and the ACM Digital Library for articles reporting mHealth app reviews and use a two-step screening process to identify eligible articles. Information on whether the authors have reported, or how they have modified the PRISMA 2020 items in their reporting, will be extracted. Data extraction will also include the article characteristics, protocol and registration information, review question frameworks used, information about the search and screening process, how apps have been evaluated and evidence of stakeholder engagement. This will be analysed using a content synthesis approach and presented using descriptive statistics and summaries. This protocol is registered on OSF (https://osf.io/5ahjx). Ethics and dissemination Ethical approval is not required. The findings will be disseminated through peer-reviewed journal publications (shared on our project website and on the EQUATOR Network website where the CAPPRRI guidance has been registered as under development), conference presentations and blog and social media posts in lay language

    Glossary of methods and terms used in analytical spectroscopy (IUPAC Recommendations 2019)

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    Recommendations are given concerning the terminology of concepts and methods used in spectroscopy in analytical chemistry, covering nuclear magnetic resonance spectroscopy, atomic spectroscopy, and vibrational spectroscopy. © 2021 IUPAC and De Gruyter. This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License. For more information, please visit: http://creativecommons.org/licenses/by-nc-nd/4.0/ 2021

    Thresholds and prediction models to support the sustainable management of herbivorous insects in wheat. A review

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    Wheat is one of the most important arable crops grown worldwide, providing a significant proportion of the daily calorific intake for countries across the globe. Wheat crops are attacked by a diverse range of herbivorous invertebrates, pests, that cause significant yield loss. It is anticipated that yield loss caused by pests will increase in response to a changing climate. Currently, these pests are primarily controlled using pesticides; however, there is an increased need for more sustainable pest management solutions. Economic thresholds represent one avenue that can support the sustainable management of pests. Briefly, thresholds are the number of pests above which there is sufficient risk of yield loss. Here, we review the economic thresholds and prediction methods available for sustainable pest management in wheat. We focus on five economically damaging pests affecting wheat crops in the UK and Europe. For each, we highlight the key period of crop risk to pest attack, identify economic thresholds, and provide an overview of current decision support models that can help estimate crop risk and advise sustainable pest management; we end by proposing areas for future improvement for each pest. Furthermore, we take a novel approach by discussing economic thresholds and their applications to sustainable pest management within the context of crop physiology and the capacity for crops to tolerate pest damage, a consideration that is often overlooked when developing pest management strategies. We use the stem-boring pest, the gout fly, as a case study and use the economic injury level equation to conduct a theoretical assessment of the appropriateness of the current gout fly threshold. This theoretical assessment indicates that wheat crops can tolerate greater gout fly damage than currently considered, and shows that by incorporating crop physiology into sustainable pest tolerance schemes we can work towards developing more appropriate physiological-based pest thresholds

    Growth and magnetic characterization of Co nanoparticles obtained by femtosecond pulsed laser deposition

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    We present a detailed study on the morphology and magnetic properties of Co nanostructures deposited onto oxidized Si substrates by femtosecond pulsed laser deposition. Generally, Co disks of nanometric dimensions are obtained just above the ablation threshold, with a size distribution characterized by an increasingly larger number of disks as their size diminishes, and with a maximum disk size that depends on the laser power density. In Au/Co/Au structures, in-plane magnetic anisotropy is observed in all cases, with no indication of superparamagnetism regardless of the amount of material or the laser power density. Magnetic force microscopy observations show coexistence of single-domain and vortex states for the magnetic domain structure of the disks. Superconducting quantum interference device magnetometry and x-ray magnetic circular dichroism measurements point to saturation magnetization values lower than the bulk, probably due to partial oxidation of the Co resulting from incomplete coverage by the Au capping layer.Work was supported in part by the U.S. Department of Energy, Basic Energy Sciences (Grant No. DE-FG02-06ER46273), NSF FOCUS Center, the Spanish Ministerio de Educación y Ciencia (References No. PR2005-0017 and No.MAT2005-05524-C02), Comunidad de Madrid (Reference No. S-0505/MAT/0194 NANOMAGNET), and CSIC (Reference No. 200650I130). Support from the SRS staff during the XMCD experiments is greatly acknowledged. Y.H. and L.M. also acknowledge financial support from the “Ramón y Cajal” and “Juan de la Cierva” programs, respectively, from the Spanish Ministerio de Investigación y Ciencia and Consejo Superior de Investigaciones Científicas (CSIC).Peer reviewe

    Anisotropic skyrmion and multi-qq spin dynamics in centrosymmetric Gd2_2PdSi3_3

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    Skyrmions are particle-like vortices of magnetization with non-trivial topology, which are usually stabilized by Dzyaloshinskii-Moriya interactions (DMI) in noncentrosymmetric bulk materials. Exceptions are centrosymmetric Gd- and Eu-based skyrmion-lattice (SkL) hosts with net-zero DMI, where both the SkL stabilization mechanisms and magnetic ground states remain controversial. We address these by investigating both static and dynamic spin properties of the centrosymmetric SkL host Gd2_2PdSi3_3 using muon spectroscopy (μ\muSR). We find that spin fluctuations in its non-coplanar SkL phase are highly anisotropic, implying that spin anisotropy plays a prominent role in stabilizing this phase. We also observe strongly-anisotropic spin dynamics in the ground-state (IC-1) incommensurate magnetic phase of the material, indicating that it is a meron-like multi-qq structure. In contrast, the higher-field, coplanar IC-2 phase is found to be single-qq with nearly-isotropic spin dynamics.Comment: Main text: 7 pages, 3 figures. Supplemental Material: 6 pages, 5 figure

    Ageing Simulation in Health and Social Care Education: A mixed methods systematic review

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    Abstract Aim: To identify, evaluate and summarise evidence from qualitative, quantitative and mixed method studies conducted utilising age-suits or other age simulation equipment, with health and social care students. Design: Convergent segregated mixed method review design as outlined by the Johanna Briggs Institute Data Sources: CINAHL (+ with Full Text), MEDLINE, PsycINFO, PubMed, SocINDEX, Web of Science, Cochrane Library, Emerald Insight, Proquest nursing, Science Direct, Wiley Online and BioMed Central (January 2000 – January 2020) Review methods: Convergent segregated synthesis was used to synthesise evidence from the studies, and the MERSQI checklist used to appraise quality. Results: A total of 23 studies were reviewed: one randomised control, two post-test only randomised control, three quasi-experimental, 15 one-group pre / post studies and two qualitative studies. Of the seventeen studies carrying out inferential statistics on attitude scores post intervention, 11 reported an improvement, three indicated no significant change and three reported worsening scores. Key themes included use of appropriate scales, type of equipment utilised, location and length of interactions, debriefing, and contextualisation of interventions in broader teaching. Conclusion: The impact of ageing simulation interventions on health and social care student’s attitudes to older people was predominantly positive. However, further high-quality research is warranted to understand the optimal use of such interventions within the context of healthcare for a growing ageing population. Impact: It is important health and social care staff have appropriate knowledge and training to enable them to provide high quality care to older people, and challenge potential ageism in the system. This review adds to the body of work around the use of simulation and experiential learning to educate health and social care students regarding ageing and ageism. It also offers recommendations for using ageing simulations effectively to inform attitudes of prospective professionals who will influence future health and social care. Keywords: Simulation, Ageing, Age-suit, Nursing, Health and social care, Education, Attitudes, Empathy, Experiential learning, Systematic revie

    Control of nanoparticle size, reactivity and magnetic properties during the bioproduction of magnetite by Geobacter sulfurreducens

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    The bioproduction of nano-scale magnetite by Fe(III)-reducing bacteria offers a potentially tunable, environmentally benign route to magnetic nanoparticle synthesis. Here, we demonstrate that it is possible to control the size of magnetite nanoparticles produced by Geobacter sulfurreducens, by adjusting the total biomass introduced at the start of the process. The particles have a narrow size distribution and can be controlled within the range of 10-50 nm. X-ray diffraction analysis indicates that controlled production of a number of different biominerals is possible via this method including goethite, magnetite and siderite, but their formation is strongly dependent upon the rate of Fe(III) reduction and total concentration and rate of Fe(II) produced by the bacteria during the reduction process. Relative cation distributions within the structure of the nanoparticles has been investigated by X-ray magnetic circular dichroism and indicates the presence of a highly reduced surface layer which is not observed when magnetite is produced through abiotic methods. The enhanced Fe(II)-rich surface, combined with small particle size, has important environmental applications such as in the reductive bioremediation of organics, radionuclides and metals. In the case of Cr(VI), as a model high-valence toxic metal, optimised biogenic magnetite is able to reduce and sequester the toxic hexavalent chromium very efficiently in the less harmful trivalent form
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