9,142 research outputs found

    Predicting the onset of rafting of c 0 precipitates by channel deformation in a Ni superalloy

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    The growth or shrinkage, normal to 001, of the interfaces between the γ matrix and cuboidal γ' precipitates is examined for a Ni-base superalloy, by considering the force acting on the interfaces. The force is produced by the precipitate coherency misfit and the stress produced by plastic deformation in channels of the γ matrix. A simple expression, which directly addresses the origin of the surface force, is given. The plastic deformation within the initially active γ matrix channels exerts the force to cause rafting. The subsequent activation of other types of channels also promotes the rafting in the same direction as the first active channels, when the plastic strain of the former channels increases. These issues are also discussed in terms of analysis based on those dislocations caused by the precipitate misfit and those produced by the plastic deformation

    Coordinated satellite and incoherent scatter observations

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    Measurements taken at the Jicamarca Radar Observatory at Lima, Peru during the Cooperative Sounding Rocket Program are reported. The following types of data were acquired: (1) electron density and temperature, (2) vertical plasma drift, (3) electrojet relative echo power density, (4) electrojet Doppler shift and condition, and (5) 150 km echoing region

    Report on coordinated satellite and incoherent scatter observations

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    Measurements taken at the Jicamarca Radar Observatory at Lima, Peru during the cooperative sounding rocket program are reported. The following types of data were acquired: (1) electron density and temperature; (2) vertical plasma drift, (3) electrojet relative echo power density; (4) electrojet doppler shift and condition; and (5) 150 km echoing region

    Compactness for Holomorphic Supercurves

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    We study the compactness problem for moduli spaces of holomorphic supercurves which, being motivated by supergeometry, are perturbed such as to allow for transversality. We give an explicit construction of limiting objects for sequences of holomorphic supercurves and prove that, in important cases, every such sequence has a convergent subsequence provided that a suitable extension of the classical energy is uniformly bounded. This is a version of Gromov compactness. Finally, we introduce a topology on the moduli spaces enlarged by the limiting objects which makes these spaces compact and metrisable.Comment: 38 page

    Systematic review of approaches to using patient experience data for quality improvement in healthcare settings

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    Objectives: Explore how patient-reported experience measures (PREMs) are collected, communicated and used to inform quality improvement (QI) across healthcare settings. Design: Systematic review. Setting: Various primary and secondary care settings, including general practice, and acute and chronic care hospitals. Participants: A full range of patient populations from (children through to the elderly) and staff (from healthcare practitioners to senior managers). Methods: Scientific databases were searched (CINAHL, PsycINFO, MEDLINE and Cochrane Libraries) as was grey literature. Qualitative and quantitative studies describing collection of PREM data and subsequent QI actions in any healthcare setting were included. Risk of bias was assessed using established criteria. Of 5312 initial hits, 32 full texts were screened, and 11 were included. Results: Patient experience data were most commonly collected through surveys and used to identify small areas of incremental change to services that do not require a change to clinician behaviour (eg, changes to admission processes and producing educational materials). While staff in most studies reported having made effective improvements, authors struggled to identify what those changes were or the impact they had. Conclusions: Findings suggest there is no single best way to collect or use PREM data for QI, but they do suggest some key points to consider when planning such an approach. For instance, formal training is recommended, as a lack of expertise in QI and confidence in interpreting patient experience data effectively may continue to be a barrier to a successful shift towards a more patient-centred healthcare service. In the context of QI, more attention is required on how patient experience data will be used to inform changes to practice and, in turn, measure any impact these changes may have on patient experience

    Disorder effects in diluted ferromagnetic semiconductors

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    Carrier induced ferromagnetism in diluted III-V semi-conductor is analyzed within a two step approach. First, within a single site CPA formalism, we calculate the element resolved averaged Green's function of the itinerant carrier. Then using a generalized RKKY formula we evaluate the Mn-Mn long-range exchange integrals and the Curie temperature as a function of the exchange parameter, magnetic impurity concentration and carrier density. The effect of the disorder (impurity scattering) appears to play a crucial role. The standard RKKY calculation (no scattering processes), strongly underestimate the Curie temperature and is inappropriate to describe magnetism in diluted magnetic semi-conductors. It is also shown that an antiferromagnetic exchange favors higher Curie temperature.Comment: tex file + 4 .eps figures are included. submited to PR

    YSOVAR: Mid-IR variability in the star forming region Lynds 1688

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    The emission from young stellar objects (YSOs) in the mid-IR is dominated by the inner rim of their circumstellar disks. We present an IR-monitoring survey of about 800 objects in the direction of the Lynds 1688 (L1688) star forming region over four visibility windows spanning 1.6 years using the \emph{Spitzer} space telescope in its warm mission phase. Among all lightcurves, 57 sources are cluster members identified based on their spectral-energy distribution and X-ray emission. Almost all cluster members show significant variability. The amplitude of the variability is larger in more embedded YSOs. Ten out of 57 cluster members have periodic variations in the lightcurves with periods typically between three and seven days, but even for those sources, significant variability in addition to the periodic signal can be seen. No period is stable over 1.6 years. Non-periodic lightcurves often still show a preferred timescale of variability which is longer for more embedded sources. About half of all sources exhibit redder colors in a fainter state. This is compatible with time-variable absorption towards the YSO. The other half becomes bluer when fainter. These colors can only be explained with significant changes in the structure of the inner disk. No relation between mid-IR variability and stellar effective temperature or X-ray spectrum is found.Comment: accepted by ApJ, 24 pages, 17 figure
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