11,617 research outputs found

    Lessons from crossing symmetry at large N

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    20 pages, v2: Assumptions stated more clearly, version published in JHEPWe consider the four-point correlator of the stress tensor multiplet in N=4 SYM. We construct all solutions consistent with crossing symmetry in the limit of large central charge c ~ N^2 and large g^2 N. While we find an infinite tower of solutions, we argue most of them are suppressed by an extra scale \Delta_{gap} and are consistent with the upper bounds for the scaling dimension of unprotected operators observed in the numerical superconformal bootstrap at large central charge. These solutions organize as a double expansion in 1/c and 1/\Delta_{gap}. Our solutions are valid to leading order in 1/c and to all orders in 1/\Delta_{gap} and reproduce, in particular, instanton corrections previously found. Furthermore, we find a connection between such upper bounds and positivity constraints arising from causality in flat space. Finally, we show that certain relations derived from causality constraints for scattering in AdS follow from crossing symmetry.Peer reviewe

    Detailed design specification for the ALT Shuttle Information Extraction Subsystem (SIES)

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    The approach and landing test (ALT) shuttle information extraction system (SIES) is described in terms of general requirements and system characteristics output products and processing options, output products and data sources, and system data flow. The ALT SIES is a data reduction system designed to satisfy certain data processing requirements for the ALT phase of the space shuttle program. The specific ALT SIES data processing requirements are stated in the data reduction complex approach and landing test data processing requirements. In general, ALT SIES must produce time correlated data products as a result of standardized data reduction or special purpose analytical processes. The main characteristics of ALT SIES are: (1) the system operates in a batch (non-interactive) mode; (2) the processing is table driven; (3) it is data base oriented; (4) it has simple operating procedures; and (5) it requires a minimum of run time information

    General practitioner empathy, patient enablement, and patient-reported outcomes in primary care in an area of high socio-economic deprivation in Scotland - a pilot prospective study using structural equation modelling

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    <b>Objective</b> The aim of this pilot prospective study was to investigate the relationships between general practitioners (GPs) empathy, patient enablement, and patient-assessed outcomes in primary care consultations in an area of high socio-economic deprivation in Scotland.<p></p> <b>Methods</b> This prospective study was carried out in a five-doctor practice in an area of high socio-economic deprivation in Scotland. Patientsā€™ views on the consultation were gathered using the Consultation and Relational Empathy (CARE) Measure and the Patient Enablement Instrument (PEI). Changes in main complaint and well-being 1 month after the contact consultation were gathered from patients by postal questionnaire. The effect of GP empathy on patient enablement and prospective change in outcome was investigated using structural equation modelling.<p></p> <b>Results</b> 323 patients completed the initial questionnaire at the contact consultation and of these 136 (42%) completed and returned the follow-up questionnaire at 1 month. Confirmatory factor analysis confirmed the construct validity of the CARE Measure, though omission of two of the six PEI items was required in order to reach an acceptable global data fit. The structural equation model revealed a direct positive relationship between GP empathy and patient enablement at contact consultation and a prospective relationship between patient enablement and changes in main complaint and well-being at 1 month.<p></p> <b>Conclusion</b> In a high deprivation setting, GP empathy is associated with patient enablement at consultation, and enablement predicts patient-rated changes 1 month later. Further larger studies are desirable to confirm or refute these findings.<p></p> <b>Practice implications</b> Ways of increasing GP empathy and patient enablement need to be established in order to maximise patient outcomes. Consultation length and relational continuity of care are known factors; the benefit of training and support for GPs needs to be further investigate

    The Ambient Horn: Designing a novel audio-based learning experience

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    The Ambient Horn is a novel handheld device designed to support children learning about habitat distributions and interdependencies in an outdoor woodland environment. The horn was designed to emit non-speech audio sounds representing ecological processes. Both symbolic and arbitrary mappings were used to represent the processes. The sounds are triggered in response to the childrenā€™s location in certain parts of the woodland. A main objective was to provoke children into interpreting and reflecting upon the significance of the sounds in the context in which they occur. Our study of the horn being used showed the sounds to be provocative, generating much discussion about what they signified in relation to what the children saw in the woodland. In addition, the children appropriated the horn in creative ways, trying to ā€˜scoopā€™ up new sounds as they walked in different parts of the woodland

    Residual stress redistribution during elastic shake down in welded plates

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    Residual stresses are a consequence of welding in various structures such as ships and offshore structures. Residual stresses can be relaxed or redistributed according to the load levels during operation. The elastic shakedown phenomenon can be considered as one of the reasons for this change. This paper studies the relaxation/redistribution of weld residual stress during different levels of shakedown in a butt-welded plate chosen according to ship design and welding procedures. Welding was performed on DH36, a ship structural steel. Neutron diffraction was used to measure residual stresses in these plates in the as-welded state and after different levels of shakedown. A mixed hardening model in line with the Chaboche model is determined for both weld and base material. A numerical model is developed to estimate the shakedown limit on butt-welded plate. Further, the redistribution of residual stress in a numerical weld model according to the different levels of shakedown limit is studied. Based on the shakedown limit of the butt-welded plate, a shakedown region is determined, where the structure will undergo elastic shakedown in the presence of an existing residual stress field if the maximum stress on the load section after a few initial cycles is in the shakedown region

    Issues in Reproducible Simulation Research

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    THE EFFECTS OF RECOVERY MODALITIES INCLUDING ICE BATH IMMERSION ON RECOVERY FROM EXERCISE AND SUBSEQUENT PERFORMANCE

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    The purpose of this study was to examine the effects of recovery modalities on recovery and subsequent performance. Ten trained male rugby union players were tested three times completing a different, randomly assigned recovery modality on each occasion. Each test began with a maximal aerobic endurance field test (20 metre shuttle test) followed by one of three recovery strategies ā€“ passive recovery, active recovery or ice bath immersion. Passive recovery involved lying on a recovery bed for 20 mins; active recovery entailed cycling for 20 mins at 50% heart rate reserve; and ice bath immersion required subjects to sit waist deep in an ice bath (5-8Ā°C) for 3 x 30 s repetitions separated by one minute standing outside the bath. Following the 45 minute post-recovery strategy period, subjects completed 6 shuttles of a timed performance test (Illinois agility test). Plasma lactate concentrations and muscle soreness ratings were measured at various intervals throughout the testing. Analysis of the data revealed that active recovery resulted in significantly greater rates of lactate removal 5 mins into the recovery strategy when compared to passive recovery (p = 0.01). Muscle soreness was significantly lower for ice bath immersion than for active recovery immediately after the 20 minute recovery period (p = 0.006). No significant differences were observed for the subsequent performance test

    Physiological Organization of Layer 4 in Macaque Striate Cortex

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    Numerous highly angled electrode penetrations through the opercular region of macaque striate cortex reveal that layers 4A, 4CĪ±, and 4CĪ²-the primary input sublaminae for axons from the lateral geniculate nucleus (LGN)-are retinotopically organized on a fine scale and populated mostly by monocularly driven cells having small receptive fields and lacking orientation selectivity. Layer 4B, which does not receive a direct thalamic input, contains orientationally selective cells, and many of these are also direction selective. To a significant degree the response properties of cells in layers 4CĪ± and 4CĪ² reflect the response properties of their respective afferent inputs, from the magno- and parvocellular laminae of the LGN. Accordingly, cells in layer 4CĪ± have lower contrast thresholds and larger minimum response fields than do the cells in layer 4CĪ² In contrast to this clear-cut separation, the cells of layer 4A (whose major source of direct LGN input arises from the parvocellular layers) exhibit both high and low contrast thresholds. With regard to the precision of retinotopic mapping that is seen in lamina 4C, it is noteworthy that there is substantial overlap among the minimum response fields of neighboring neurons. Due to a larger mean receptive field size, this overlap is greater in layer 4CĪ± than it is in 4CĪ². In either sublamina, however, the minimum cortical distance that separates different and nonoverlapping parts of the visual field corresponds closely-within a factor of 2-to the known arborizational spreads of single geniculate afferents

    Diffusion Bonding Aeroengine Components

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