891 research outputs found

    Observation of a Triangular to Square Flux Lattice Phase Transition in YBCO

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    We have used the technique of small-angle neutron scattering to observe magnetic flux lines directly in an YBCO single crystal at fields higher than previously reported. For field directions close to perpendicular to the CuO2 planes, we find that the flux lattice structure changes smoothly from a distorted triangular co-ordination to nearly perfectly square as the magnetic induction approaches 11 T. The orientation of the square flux lattice is as expected from recent d-wave theories, but is 45 deg from that recently observed in LSCO

    Improving quality and equity in schools in socially disadvantaged areas

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    Background: Recent effectiveness studies have investigated the relationship between two dimensions of effectiveness - namely, quality and equity. Specifically, the question of whether effective schools can also reduce the initial differences in student outcomes attributed to student background factors has been examined. In this context, the Dynamic Approach to School Improvement (DASI) makes use of theory and the research findings of effectiveness studies to try to improve school effectiveness in terms of quality and equity. Purpose: This study aimed to examine whether the implementation of DASI in primary schools in socially disadvantaged areas in four European countries (Cyprus, England, Greece and Ireland) was able to promote student learning outcomes in mathematics and to reduce the impact of student background factors on student achievement in mathematics. Design and methods: A sample of 72 primary schools across the four countries was randomly split into experimental and control groups. At the beginning and at the end of the school year, mathematics tests were administered to all students of Grades 4-6 (n = 5560; student ages 9-12 years). The experimental group made use of DASI. Within-country multilevel regression analyses were conducted to evaluate the impact of the intervention and search for interaction effects between the use of DASI and student background factors on final achievement. Results: In each country, the experimental group achieved better results in mathematics than the control group. At the beginning of the intervention, the achievement gap based on socio-economic status (SES) was equally large in the experimental and the control groups. Only in the experimental group did the achievement gap based on SES become smaller. However, DASI was not found to have an effect on equity when the equity dimension was examined by focusing on the achievement gap based on either gender or ethnicity. Conclusions: Implications of findings are drawn and the importance of measuring equity in terms of student achievement gaps based on different background factors, rather than only on SES, is emphasised. We propose the evaluation of the impact of interventions on promoting equity by the use of various criteria

    MRAP deficiency impairs adrenal progenitor cell differentiation and gland zonation

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    Melanocortin 2 receptor accessory protein (MRAP) is a single transmembrane domain accessory protein and a critical component of the hypothamo-pituitary-adrenal axis. MRAP is highly expressed in the adrenal gland and is essential for adrenocorticotropin hormone (ACTH) receptor expression and function. Human loss-of-function mutations in MRAP cause familial glucocorticoid (GC) deficiency (FGD) type 2 (FGD2), whereby the adrenal gland fails to respond to ACTH and to produce cortisol. In this study, we generated Mrap-null mice to study the function of MRAP in vivo. We found that the vast majority of Mrap−/− mice died at birth but could be rescued by administration of corticosterone to pregnant dams. Surviving Mrap−/− mice developed isolated GC deficiency with normal mineralocorticoid and catecholamine production, recapitulating FGD2. The adrenal glands of adult Mrap−/− mice were small, with grossly impaired adrenal capsular morphology and cortex zonation. Progenitor cell differentiation was significantly impaired, with dysregulation of WNT4/β-catenin and sonic hedgehog pathways. These data demonstrate the roles of MRAP in both steroidogenesis and the regulation of adrenal cortex zonation. This is the first mouse model of isolated GC deficiency and reveals the role of MRAP in adrenal progenitor cell regulation and cortex zonatio

    The effects of dietary hesperidin and naringin supplementation on lamb performance and meat characteristics

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    An experiment was conducted to examine the effects of supplementing feed with hesperidin or naringin, bioflavonoids that are abundant and inexpensive by-products of citrus cultivation, on lambs’ growth performance, carcass and meat characteristics. Fourty-four male Chios lambs were randomly assigned to 4 groups. One of the groups served as control (C) and was given a basal diet, whereas the other 3 groups were given the same diet further supplemented with hesperidin at 2500 mg (H), or naringin at 2500 mg (N), or α-tocopheryl acetate at 200 mg (E) per kg feed. At the end of the experiment (35th day), lambs were fasted, weighed and slaughtered. After overnight chilling, samples of longissimus thoracis muscle were taken and were used for meat quality evaluation. No significant differences were observed in final body weight, body weight gain and edible organ weights among the four experimental groups. pH, colour parameters (L, a*, b*), water holding capacity and shear force value of longissimus thoracis muscle were also not significantly influenced by the dietary treatments. Measurement of lipid oxidation values showed that hesperidin or naringin supplementation positively influenced meat antioxidant properties during the refrigerated storage at 4°C for up to 8 days, however to a lesser extent compared to α-tocopheryl acetate. Nowadays, there is a strong interest in isolating antioxidants from natural sources and using them in animal nutrition with the intention to minimize lipid oxidation in meat products. According to the findings of the present study, flavonoids appeared as a great alternative, since they resulted in an improvement of meat antioxidant capacity leading to a prolongation of its shelf-life and an increase of its acceptability in the market

    Is there a vortex-glass transition in high-temperature superconductors?

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    We show that DC voltage versus current measurements of a YBCO micro-bridge in a magnetic field can be collapsed onto scaling functions proposed by Fisher, Fisher, and Huse, as is widely reported in the literature. We find, however, that good data collapse is achieved for a wide range of critical exponents and temperatures. These results strongly suggest that agreement with scaling alone does not prove the existence of a phase transition. We propose a criterion to determine if the data collapse is valid, and thus if a phase transition occurs. To our knowledge, none of the data reported in the literature meet our criterion.Comment: 4 pages, 4 figure

    Cementing Techniques In Knee Surgery (CeTIKS) : a UK expert consensus study

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    © 2023 Author(s) et al.AIMS: Aseptic loosening is the most common cause of failure following cemented total knee arthroplasty (TKA), and has been linked to poor cementation technique. We aimed to develop a consensus on the optimal technique for component cementation in TKA. METHODS: A UK-based, three-round, online modified Delphi Expert Consensus Study was completed focusing on cementation technique in TKA. Experts were identified as having a minimum of five years' consultant experience in the NHS and fulfilling any one of the following criteria: a 'high volume' knee arthroplasty practice (> 150 TKAs per annum) as identified from the National joint Registry of England, Wales, Northern Ireland and the Isle of Man; a senior author of at least five peer reviewed articles related to TKA in the previous five years; a surgeon who is named trainer for a post-certificate of comletion of training fellowship in TKA. RESULTS: In total, 81 experts (round 1) and 80 experts (round 2 and 3) completed the Delphi Study. Four domains with a total of 24 statements were identified. 100% consensus was reached within the cement preparation, pressurization, and cement curing domains. 90% consensus was reached within the cement application domain. Consensus was not reached with only one statement regarding the handling of cement during initial application to the tibial and/or femoral bone surfaces. CONCLUSION: The Cementing Techniques In Knee Surgery (CeTIKS) Delphi consensus study presents comprehensive recommendations on the optimal technique for component cementing in TKA. Expert opinion has a place in the hierarchy of evidence and, until better evidence is available these recommendations should be considered when cementing a TKA.Peer reviewe

    Inter-observer agreement of canine and feline paroxysmal event semiology and classification by veterinary neurology specialists and non-specialists

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    Background: Advances in mobile technology mean vets are now commonly presented with videos of paroxysmal events by clients, but the consistency of the interpretation of these videos has not been investigated. The objective of this study was to investigate the level of agreement between vets (both neurology specialists and non-specialists) on the description and classification of videos depicting paroxysmal events, without knowing any results of diagnostic workup. An online questionnaire study was conducted, where participants watched 100 videos of dogs and cats exhibiting paroxysmal events and answered questions regarding: epileptic seizure presence (yes/ no), seizure type, consciousness status, and the presence of motor, autonomic and neurobehavioural signs. Agreement statistics (percentage agreement and kappa) calculated for each variable, with prevalence indices calculated to aid their interpretation. Results: Only a fair level of agreement (kappa = 0.40) was found for epileptic seizure presence. Overall agreement of seizure type was moderate (kappa = 0.44), with primary generalised seizures showing the highest level of agreement (kappa = 0.60), and focal the lowest (kappa = 0.31). Fair agreement was found for consciousness status and the presence of autonomic signs (kappa = 0.21-0.40), but poor agreement for neurobehavioral signs (kappa = 0.16). Agreement for motor signs ranged from poor (kappa = <= 0.20) to moderate (kappa = 0.41-0.60). Differences between specialists and non-specialists were identified. Conclusions: The relatively low levels of agreement described here highlight the need for further discussions between neurology experts regarding classifying and describing epileptic seizures, and additional training of non-specialists to facilitate accurate diagnosis. There is a need for diagnostic tools (e.g. electroencephalogram) able to differentiate between epileptic and non-epileptic paroxysms

    Muons as Local Probes of Three-body Correlations in the Mixed State of Type-II Superconductors

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    The vortex glass state formed by magnetic flux lines in a type-II superconductor is shown to possess non-trivial three-body correlations. While such correlations are usually difficult to measure in glassy systems, the magnetic fields associated with the flux vortices allow us to probe these via muon-spin rotation measurements of the local field distribution. We show via numerical simulations and analytic calculations that these observations provide detailed microscopic insight into the local order of the vortex glass and more generally validate a theoretical framework for correlations in glassy systems.Comment: 4+ pages, high-quality figures available on reques

    Phase diagrams of flux lattices with disorder

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    We review the prediction, made in a previous work [Phys. Rev. B 52 (1995)], that the phase diagram of type II superconductors consists of a topologically ordered Bragg glass phase at low fields undergoing a transition at higher fields into a vortex glass or a liquid. We estimate the position of the phase boundary using a Lindemann criterion. We find that the proposed phenomenology is compatible with recent experiments on superconductors.Comment: 7 pages 2 figures, uses epsfi

    Systematic review of antiepileptic drugs’ safety and effectiveness in feline epilepsy

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    Understanding the efficacy and safety profile of antiepileptic drugs (AEDs) in feline epilepsy is a crucial consideration for managing this important brain disease. However, there is a lack of information about the treatment of feline epilepsy and therefore a systematic review was constructed to assess current evidence for the AEDs’ efficacy and tolerability in cats. The methods and materials of our former systematic reviews in canine epilepsy were mostly mirrored for the current systematic review in cats. Databases of PubMed, CAB Direct and Google scholar were searched to detect peer-reviewed studies reporting efficacy and/or adverse effects of AEDs in cats. The studies were assessed with regards to their quality of evidence, i.e. study design, study population, diagnostic criteria and overall risk of bias and the outcome measures reported, i.e. prevalence and 95% confidence interval of the successful and affected population in each study and in total
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