Spin Amplification for Magnetic Sensors Employing Crystal Defects

Recently there have been several theoretical and experimental studies of the prospects for magnetic field sensors based on crystal defects, especially nitrogen vacancy (NV) centres in diamond. Such systems could potentially be incorporated into an AFM-like apparatus in order to map the magnetic properties of a surface at the single spin level. In this Letter we propose an augmented sensor consisting of an NV centre for readout and an `amplifier' spin system that directly senses the local magnetic field. Our calculations show that this hybrid structure has the potential to detect magnetic moments with a sensitivity and spatial resolution far beyond that of a simple NV centre, and indeed this may be the physical limit for sensors of this class

Magnetic buoyancy in simulated galactic discs with a realistic circum galactic medium

We present simulations of isolated disc galaxies in a realistic environment performed with the Tree-SPMHD-Code Gadget-3. Our simulations include a spherical circum-galactic medium (CGM) surrounding the galactic disc, motivated by observations and the results of cosmological simulations. We present three galactic models with different halo masses between 10e10 Msol and 10e12 Msol, and for each we use two different approaches to seed the magnetic field, as well as a control simulation without a magnetic field. We find that the amplification of the magnetic field in the centre of the disc leads to a biconical magnetic outflow of gas that magnetizes the CGM. This biconical magnetic outflow reduces the star formation rate (SFR) of the galaxy by roughly 40 percent compared to the simulations without magnetic fields. As the key aspect of our simulations, we find that small scale turbulent motion of the gas in the disc leads to the amplification of the magnetic field up to tens of 10e-6 G, as long as the magnetic field strength is low. For stronger magnetic fields turbulent motion does not lead to significant amplification but is replaced by an alpha-omega dynamo. The occurance of a small scale turbulent dynamo becomes apparent through the magnetic power spectrum and analysis of the field lines' curvature. In accordance with recent observations we find an anti-correlation between the spiral structure in the gas density and in the magnetic field due to a diffusion term added to the induction equation.Comment: 22 pages, 16 figures, submitted to MNRA

Ensemble based quantum metrology

The field of quantum metrology promises measurement devices that are fundamentally superior to conventional technologies. Specifically, when quantum entanglement is harnessed the precision achieved is supposed to scale more favourably with the resources employed, such as system size and the time required. Here we consider measurement of magnetic field strength using an ensemble of spins, and we identify a third essential resource: the initial system polarisation, i.e. the low entropy of the original state. We find that performance depends crucially on the form of decoherence present; for a plausible dephasing model, we describe a quantum strategy which can indeed beat the standard quantum limit

Quantum metrology with molecular ensembles

This work was supported by the EPSRC through QIP IRC (Grants No. GR/S82176/01 and No. GR/S15808/01), the National Research Foundation and Ministry of Education, Singapore, the DAAD, and the Royal Society.The field of quantum metrology promisesmeasurement devices that are fundamentally superior to conventional technologies. Specifically, when quantum entanglement is harnessed, the precision achieved is supposed to scale more favorably with the resources employed, such as system size and time required. Here, we consider measurement of magnetic-field strength using an ensemble of spin-active molecules. We identify a third essential resource: the change in ensemble polarization (entropy increase) during the metrology experiment. We find that performance depends crucially on the form of decoherence present; for a plausible dephasing model, we describe a quantum strategy, which can indeed beat the standard strategy.Publisher PDFPeer reviewe

Development of an optimised physiotherapist-led treatment protocol for lateral elbow tendinopathy:a consensus study using an online nominal group technique

OBJECTIVES: There are a wide range of physiotherapy treatment options for people with lateral elbow tendinopathy (LET); however, previous studies have reported inconsistent approaches to treatment and a lack of evidence demonstrating clinical effectiveness. This study aimed to combine the best available research evidence with stakeholder perspectives to develop key components of an optimised physiotherapist-led treatment protocol for testing in a future randomised controlled trial (RCT). DESIGN: Online consensus groups using nominal group technique (NGT), a systematic approach to building consensus using structured multistage meetings. SETTING: UK National Health Service (NHS). PARTICIPANTS: 10 physiotherapists with special interest in LET, 2 physiotherapy service managers and 3 patients who had experienced LET. INTERVENTIONS: Two consensus groups were conducted; the first meeting focused on agreeing the types of interventions to be included in the optimised treatment protocol; the second meeting focused on specific details of intervention delivery. Participants were sent an evidence summary of available treatments for LET prior to the first meeting. All treatment options were discussed before anonymous voting and ranking of priority. Consensus for inclusion of each treatment option was set at ≥70% based on OMERACT guidelines. Options with 30%-69% agreement were discussed again, and a second vote was held, allowing for a change of opinion. RESULTS: The optimised physiotherapist-led treatment package included: advice and education, exercise therapy and orthotics. Specific components for each of these interventions were also agreed such as: condition-specific advice, health-promotion advice, exercise types, exercise into 'acceptable' levels of pain, exercise dosage and type of orthoses. Other treatment options including electrotherapy, acupuncture and manual therapy were excluded. CONCLUSION: An optimised physiotherapist-led treatment protocol for people with LET was successfully developed using an online NGT consensus approach. This intervention is now ready for testing in a future pilot/feasibility RCT to contribute much needed evidence about the treatment of LET. TRIAL REGISTRATION NUMBER: This is the pre-cursor to the OPTimisE Pilot and Feasibility Randomised Controlled Trial. Registration: https://www.isrctn.com/ISRCTN64444585

The Lived Experience of People with Lateral Elbow Tendinopathy – a Qualitative Study from the OPTimisE Pilot & Feasibility Trial.

Objectives: To explore the lived experience of people with lateral elbow tendinopathy (LET) and its impact on everyday life. Design: Qualitative semi-structured interviews, analysed using thematic analysis. Setting: Conducted as part of the mixed-methods OPTimisE pilot and feasibility randomised controlled trial of outpatient physiotherapy patients in the UK. Participants: 17 participants with LET, purposively sampled from the trial to provide representativeness based on age, sex, ethnicity, deprivation index and treatment allocation. Results: Four themes were identified from the participants’ responses: (1) cause of onset—typically symptoms were attributed to: sudden changes in activity, repetitive work or compensating for other musculoskeletal conditions; (2) impact on everyday life—which included substantial impacts on quality-of-life, particularly due to pain disturbing sleep and difficulties performing daily tasks (related to work and hobbies) due to pain, although most reported being able to persevere with work; (3) self-help and understanding of the condition—with uncertainty about the appropriateness and potential harm of online advice and confusion from the diagnostic term ‘Tennis Elbow’ that non-sporting individuals struggled to relate to; (4) healthcare experiences—the treatments received were highly variable and often perceived as ineffectual. Conclusions: For the first time, the lived experience of people from a range of backgrounds suffering from LET has been explored. Findings suggest that people frequently related the cause to a specific activity. They reported substantial impacts on daily tasks, sleep, work and hobbies. People also reported hesitancy to trust online information without formal healthcare advice, were confused by the common label of ‘Tennis Elbow’, and perceived the wide array of healthcare treatment options they had received to offer false hope and be largely ineffective. This study provides stimulus for clinicians to consider the advice and treatment provided, and whether the messages conveyed reflect the favourable natural history of the condition. Trial registration number: ISRCTN6444458

Exploring the feasibility and acceptance of an optimised physiotherapy approach for lateral elbow tendinopathy: a qualitative investigation within the OPTimisE trial

Objectives: To explore the acceptability of an optimised physiotherapy (OPTimisE) intervention for people with lateral elbow tendinopathy (LET) and feasibility of comparing it to usual care in a randomised controlled trial. Design: Semistructured interviews, analysed using thematic analysis and mapped onto the COM-B model of behaviour change. Setting: Conducted as part of the OPTimisE Pilot & Feasibility randomised controlled trial within physiotherapy departments in the United Kingdom National Health Service. Participants: 17 patients with LET (purposively sampled to provide representativeness based on age, sex, ethnicity, deprivation index and treatment allocation) and all 8 physiotherapists involved as treating clinicians or site principal investigators. Results: Four themes were identified. First, participants reported the OPTimisE intervention as acceptable. Second, differences between the OPTimisE intervention and usual care were identified, including the use of an orthosis, holistic advice/education including modifiable risk factors, forearm stretches, general upper body strengthening and a more prescriptive exercise-dosing regimen. Third, participants provided feedback related to the trial resources, which were viewed positively, but identified language translation as a need. Fourth, feedback related to trial processes identified the need for changes to outcome collection and reduction of administrative burden. From the perspective of adopting the OPTimisE intervention, we found evidence that participants were able to change their behaviour. Considering the findings through the lens of the COM-B model, the intervention is likely to be deliverable in practice and the trial can be delivered at scale with some additional support for physiotherapists. Conclusions: Overall, the OPTimisE intervention was found to be different to usual care and acceptable to patients and physiotherapists. The study highlighted the need to refine trial processes and resources prior to a full-scale trial, to reduce administrative burden, increase support for physiotherapists, improve return rate of outcome questionnaires and provide language translation. Trial registration number: ISRCTN database 19 July 2021. https://www.isrctn.com/ISRCTN64444585

Conceptual Change in Science Teaching and Learning: Introducing the Dynamic Model of Conceptual Change

Conceptual change can be a challenging process, particularly in science education where many of the concepts are complex, controversial, or counter-intuitive.  Yet, conceptual change is fundamental to science learning, which suggests science educators and science education researchers need models to effectively address and investigate conceptual change.  Consideration of the current research and extant models of conceptual change reflect a need for a holistic, comprehensive, and dynamic model of conceptual change.  In response, we developed the Dynamic Model of Conceptual Change (DMCC), which uses multiple lines of research that explore the variables influencing conceptual change and the dynamic interactions that take place during the conceptual change process in science teaching and learning.  Unique to the DMCC is the potential for iterations, regression, enter and exit points at various stages of the conceptual change process, and the influences of message recognition, message engagement and processing, and the nature of the resulting conceptual change.  The DMCC contains elements from extant models along with previously un-emphasized influential conceptual change variables such as culture, society, attitude, practices, and personal epistemology.  We constructed the DMCC to provide science educators and researchers a more holistic framework for exploring conceptual change in science instruction and learning

Effects of Air Pollution Control on Climate

Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).Urban air pollution and climate are closely connected due to shared generating processes (e.g., combustion) for emissions of the driving gases and aerosols. They are also connected because the atmospheric lifecycles of common air pollutants such as CO, NOx and VOCs, and of the climatically important methane gas (CH4) and sulfate aerosols, both involve the fast photochemistry of the hydroxyl free radical (OH). Thus policies designed to address air pollution may impact climate and vice versa. We present calculations using a model coupling economics, atmospheric chemistry, climate and ecosystems to illustrate some effects of air pollution policy alone on global warming. We consider caps on emissions of NOx, CO, volatile organic carbon, and SOx both individually and combined in two ways. These caps can lower ozone causing less warming, lower sulfate aerosols yielding more warming, lower OH and thus increase CH4 giving more warming, and finally, allow more carbon uptake by ecosystems leading to less warming. Overall, these effects significantly offset each other suggesting that air pollution policy has a relatively small net effect on the global mean surface temperature and sea level rise. However, our study does not account for the effects of air pollution policies on overall demand for fossil fuels and on the choice of fuels (coal, oil, gas), nor have we considered the effects of caps on black carbon or organic carbon aerosols on climate. These effects, if included, could lead to more substantial impacts of capping pollutant emissions on global temperature and sea level than concluded here. Caps on aerosols in general could also yield impacts on other important aspects of climate beyond those addressed here, such as the regional patterns of cloudiness and precipitation.This research was supported by the U.S Department of Energy, U.S. National Science Foundation, and the Industry Sponsors of the MIT Joint Program on the Science and Policy of Global Change: Alstom Power (France), American Electric Power (USA), BP p.l.c. (UK/USA), ChevronTexaco Corporation (USA), DaimlerChrysler AG (Germany), Duke Energy (USA), J-Power (Electric Power Development Co., Ltd.) (Japan), Electric Power Research Institute (USA), Electricité de France, ExxonMobil Corporation (USA), Ford Motor Company (USA), General Motors (USA), Mirant (USA), Murphy Oil Corporation (USA), Oglethorpe Power Corporation (USA), RWE/Rheinbraun (Germany), Shell International Petroleum (Netherlands/UK), Statoil (Norway), Tennessee Valley Authority (USA), Tokyo Electric Power Company (Japan), TotalFinaElf (France), Vetlesen Foundation (USA)

Examining solution and solid state composition for the solution mediated polymorphic transformation of carbamazepine and piracetam

peer-reviewedSolution mediated polymorphic transformations (SMPT) of the pharmaceutical compounds carbamazepine and piracetam have been investigated. Seeded transformation experiments were performed, and the solution concentration was monitored by in situ infra-red spectroscopy using a calibration free method. Solid samples were also taken over time, and the percentage of metastable and stable polymorphic phases were determined using off line quantitative powder X-ray diffraction analysis. Solution and solid state data were compared for each compound. In the case of carbamazepine, the SMPT from FI to FIII was identified as being controlled by the growth of the stable FIII polymorph. For piracetam, the SMPT was also identified as being controlled by growth of the stable polymorph, but with a more considerable induction time for nucleation of the stable phase. This paper demonstrates how the rate determining steps of the SMPT can be identified if both solution and solid phase data are recorded. The results are compared with other studies reported in the literature and rationalized into four principal scenarios