57,679 research outputs found

    Applying hierarchical task analysis to medication administration errors

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    Medication use in hospitals is a complex process and is dependent on the successful interaction of health professionals functioning within different disciplines. Errors can occur at any one of the five main stages of prescribing, documenting, dispensing or preparation, administering and monitoring. The responsibility for the error is often placed on the nurse, as she or he is the last person in the drug administration chain whilst more pressing underlying causal factors remain unresolved. This paper demonstrates how hierarchical task analysis can be used to model drug administration and then uses the systematic human error reduction and prediction approach to predict which errors are likely to occur. The paper also puts forward design solutions to mitigate these errors

    Bored with point and click?

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    Computers have the potential to be exploited as one of the most exciting examples of instructional media. Yet designers often fail to realize this potential. This is, in part, due to the limitations of hardware and software and, in part, due to the lack of good theory developed through conclusive research. Good examples of computer-based learning may owe more to the imaginative flair of the courseware designer than they do to the application of explicit design guidelines and good learning theory. This paper will therefore consider a variety of issues that may be blocking theoretical development and draw conclusions for future courses of action. This starts with a statement of the problem, first by considering the macro and micro issues, and then by looking at a recent call for help in ComputerBased Learning Environment (CBLE) design. Next, the contribution of instructional design theories will be presented together with a way forward for investigating the issues. Finally the implications for future progress are presented

    Isospin Mixing and Model Dependence

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    We show that recent calculations of \Delta I=3/2 effects in nonleptonic hyperon decay induced by m_d-m_u\neq 0 are subject to significant model dependence.Comment: 8 page standard Latex fil

    A self excitation and control system for wind tunnel dynamic stability measurements

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    The paper describes the design and development of a fast acting self-excitation and control system based on the principles of regenerative and negative feedback for phase resonance testing of aerodynamic models in wind tunnels. Simulation tests and analyses using a linearized model of the drive system are carried out, and results indicate that the system would function even if the system damping becomes neutral or negative. Experiments for dynamic stability measurements show that the control system meets all specifications and performs satisfactorily even in the presence of moderate amounts of turbulence in the air flow

    Astrocytic LRP1 mediates brain Aβ clearance and impacts amyloid deposition

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    Accumulation and deposition of amyloid-β (Aβ) in the brain represent an early and perhaps necessary step in the pathogenesis of Alzheimer's disease (AD). Aβ accumulation leads to the formation of Aβ aggregates, which may directly and indirectly lead to eventual neurodegeneration. While Aβ production is accelerated in many familial forms of early-onset AD, increasing evidence indicates that impaired clearance of Aβ is more evident in late-onset AD. To uncover the mechanisms underlying impaired Aβ clearance in AD, we examined the role of low-density lipoprotein receptor-related protein 1 (LRP1) in astrocytes. Although LRP1 has been shown to play critical roles in brain Aβ metabolism in neurons and vascular mural cells, its role in astrocytes, the most abundant cell type in the brain responsible for maintaining neuronal homeostasis, remains unclear. Here, we show that astrocytic LRP1 plays a critical role in brain Aβ clearance. LRP1 knockdown in primary astrocytes resulted in decreased cellular Aβ uptake and degradation. In addition, silencing of LRP1 in astrocytes led to downregulation of several major Aβ-degrading enzymes, including matrix metalloproteases MMP2, MMP9, and insulin-degrading enzyme. More important, conditional knock-out of theLrp1gene in astrocytes in the background of APP/PS1 mice impaired brain Aβ clearance, exacerbated Aβ accumulation, and accelerated amyloid plaque deposition without affecting its production. Together, our results demonstrate that astrocytic LRP1 plays an important role in Aβ metabolism and that restoring LRP1 expression and function in the brain could be an effective strategy to facilitate Aβ clearance and counter amyloid pathology in AD.SIGNIFICANCE STATEMENTAstrocytes represent a major cell type regulating brain homeostasis; however, their roles in brain clearance of amyloid-β (Aβ) and underlying mechanism are not clear. In this study, we used both cellular models and conditional knock-out mouse models to address the role of a critical Aβ receptor, the low-density lipoprotein receptor-related protein 1 (LRP1) in astrocytes. We found that LRP1 in astrocytes plays a critical role in brain Aβ clearance by modulating several Aβ-degrading enzymes and cellular degradation pathways. Our results establish a critical role of astrocytic LRP1 in brain Aβ clearance and shed light on specific Aβ clearance pathways that may help to establish new targets for AD prevention and therapy.</jats:p

    Charmed-Baryon Spectroscopy from Lattice QCD with N_f=2+1+1 Flavors

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    We present the results of a calculation of the positive-parity ground-state charmed-baryon spectrum using 2+1+1 flavors of dynamical quarks. The calculation uses a relativistic heavy-quark action for the valence charm quark, clover-Wilson fermions for the valence light and strange quarks, and HISQ sea quarks. The spectrum is calculated with a lightest pion mass around 220 MeV, and three lattice spacings (a \approx 0.12 fm, 0.09 fm, and 0.06 fm) are used to extrapolate to the continuum. The light-quark mass extrapolation is performed using heavy-hadron chiral perturbation theory up to O(m_pi^3) and at next-to-leading order in the heavy-quark mass. For the well-measured charmed baryons, our results show consistency with the experimental values. For the controversial J=1/2 Xi_{cc}, we obtain the isospin-averaged value M_{Xi_{cc}}=3595(39)(20)(6) MeV (the three uncertainties are statistics, fitting-window systematic, and systematics from other lattice artifacts, such as lattice scale setting and pion-mass determination), which shows a 1.7 sigma deviation from the experimental value. We predict the yet-to-be-discovered doubly and triply charmed baryons Xi_{cc}^*, Omega_{cc}, Omega_{cc}^* and Omega_{ccc} to have masses 3648(42)(18)(7) MeV, 3679(40)(17)(5) MeV, 3765(43)(17)(5) MeV and 4761(52)(21)(6) MeV, respectively.Comment: 23 pages, 14 figure
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