912 research outputs found

    Extended scope of nursing practice: a multicentre randomised controlled trial of appropriately trained nurses and pre-registration house officers in pre-operative assessment in elective general surgery

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    Aim/ Principal Research Question:1) To determine whether pre-operative assessment carried out by an appropriately trained nurse (ATN) is equivalent in quality to that carried out by a pre-registration house officer (PRHO).2) To assess whether pre-assessments carried out by ATNs and PRHOs are equivalent in terms of cost.3) To determine whether assessments carried out by ATNs are acceptable to patients.4) To investigate the quality of communication between senior medical staff and ATNs.Factors of Interest:The extended role of appropriately trained nurses and pre-registration house officers in pre-operative assessment in elective general surgery.Methods:The study design was principally a prospective randomised equivalence trial but was accompanied by additional qualitative assessment of patient and staff perceptions, and an economic evaluation.The intervention consisted of a pre-operative assessment carried out by either an ATN or a PRHO. Of the patients who completed the study with a full evaluation, 926 patients were randomised to the PRHO arm of the trial and 948 to the ATN arm. Three ATNs took part in the study, one from each centre, together with a total of 87 PRHOs.Immediately following the initial assessment of a patient by a PRHO or an ATN, one of a number of clinical research fellows, all specialist registrars in anaesthetics, repeated the assessment and recorded it on a study form, together with a list of investigations required. The clinical research fellow then evaluated the competency of the initial assessor by comparing the quality of their assessment with their own. Any deficiencies in ordering of investigations and referral to other specialities were met in order to maximise patient care.Sample groups:All patients attending at one site for assessment prior to general anaesthetic for elective general, vascular, urological or breast surgery were potentially included in the study. Of 1907 patients who were randomised, 1874 completed the study with a full evaluation.The study was carried out at four NHS hospitals, three of which were teaching hospitals, in three NHS Trusts in Southampton, Sheffield and Doncaster.Outcome measures:Three areas of ATN and PRHO performance were judged separately, history taking, examination and ordering of tests, and each was graded into one of four categories, the most important of which was under-assessment, which would possibly have affected peri-operative management. In the case of ordering of tests, it was possible to have both over- and under-assessed a patient on different tests.Findings:The pre-operative assessments carried out by the ATNs were essentially equivalent to those performed by the PRHOs in terms of under-assessment that might possibly have affected peri-operative management, although there was variation between the ATNs in terms of the quality of history taking. This may be related to the low number of patients seen at one study site.PRHOs ordered significantly more unnecessary tests than the ATNs. The substitution of ATNs for PRHOs was calculated to be cost neutral.The results of the qualitative assessment showed that the use of ATNs for pre-operative assessment was acceptable to patients; however, there was no evidence that communication between senior medical staff and those carrying out pre-operative assessments was improved by their introduction.Conclusions:This study demonstrated no reason to inhibit the development of fully nurse-led pre-operative assessment, provided that the nurses are appropriately trained and maintain sufficient workload to retain skills.Implications for Further Research:Further research is needed in the following areas:1) the extent and type of training needed for nurses undertaking the pre-operative assessment role2) the use, costs and benefits of routine pre-operative testing.<br/

    Structure and Thermodynamics of the Mixed Alkali Alanates

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    The thermodynamics and structural properties of the hexahydride alanates (M2M'AlH6) with the elpasolite structure have been investigated. A series of mixed alkali alanates (Na2LiAlH6, K2LiAlH6 and K2NaAlH6) were synthesized and found to reversibly absorb and desorb hydrogen without the need for a catalyst. Pressure-composition isotherms were measured to investigate the thermodynamics of the absorption and desorption reactions with hydrogen. Isotherms for catalyzed (4 mol% TiCl3) and uncatalyzed Na2LiAlH6 exhibited an increase in kinetics, but no change in the bulk thermodynamics with the addition of a dopant. A structural analysis using synchrotron x-ray diffraction showed that these compounds favor the Fm-3m space group with the smaller ion (M') occupying an octahedral site. These results demonstrate that appropriate cation substitutions can be used to stabilize or destabilize the material and may provide an avenue to improving the unfavorable thermodynamics of a number of materials with promising gravimetric hydrogen densities.Comment: 6 pages, 7 figures,3 tables, submitted to PR

    Ferromagnetic Luttinger Liquids

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    We study weak itinerant ferromagnetism in one-dimensional Fermi systems using perturbation theory and bosonization. We find that longitudinal spin fluctuations propagate ballistically with velocity v_m << v_F, where v_F is the Fermi velocity. This leads to a large anomalous dimension in the spin-channel and strong algebraic singularities in the single-particle spectral function and in the transverse structure factor for momentum transfers q ~ 2 Delta/v_F, where 2 Delta is the exchange splitting.Comment: 4 pages, 3 figure

    Spin-dependent thermoelectric transport coefficients in near-perfect quantum wires

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    Thermoelectric transport coefficients are determined for semiconductor quantum wires with weak thickness fluctuations. Such systems exhibit anomalies in conductance near 1/4 and 3/4 of 2e^2/h on the rising edge to the first conductance plateau, explained by singlet and triplet resonances of conducting electrons with a single weakly bound electron in the wire [T. Rejec, A. Ramsak, and J.H. Jefferson, Phys. Rev. B 62, 12985 (2000)]. We extend this work to study the Seebeck thermopower coefficient and linear thermal conductance within the framework of the Landauer-Buettiker formalism, which also exhibit anomalous structures. These features are generic and robust, surviving to temperatures of a few degrees. It is shown quantitatively how at elevated temperatures thermal conductance progressively deviates from the Wiedemann-Franz law.Comment: To appear in Phys. Rev. B 2002; 3 figure

    New Route to Local Order Models for Disordered Crystalline Materials: Diffuse Scattering and Computational Modeling of Phloroglucinol Dihydrate

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    A new, readily tractable route to determining short-range order models for materials exhibiting occupational disorder and diffuse scattering using first-principles solid-state quantum mechanical calculations is presented and illustrated with application to the disordered, layered molecular material phloroglucinol dihydrate

    Extreme sensitivity of the spin-splitting and 0.7 anomaly to confining potential in one-dimensional nanoelectronic devices

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    Quantum point contacts (QPCs) have shown promise as nanoscale spin-selective components for spintronic applications and are of fundamental interest in the study of electron many-body effects such as the 0.7 x 2e^2/h anomaly. We report on the dependence of the 1D Lande g-factor g* and 0.7 anomaly on electron density and confinement in QPCs with two different top-gate architectures. We obtain g* values up to 2.8 for the lowest 1D subband, significantly exceeding previous in-plane g-factor values in AlGaAs/GaAs QPCs, and approaching that in InGaAs/InP QPCs. We show that g* is highly sensitive to confinement potential, particularly for the lowest 1D subband. This suggests careful management of the QPC's confinement potential may enable the high g* desirable for spintronic applications without resorting to narrow-gap materials such as InAs or InSb. The 0.7 anomaly and zero-bias peak are also highly sensitive to confining potential, explaining the conflicting density dependencies of the 0.7 anomaly in the literature.Comment: 23 pages, 7 figure

    SS25. Cryopreserved Venous Allograft: An Alternative Conduit for Reconstruction of Infected Prosthetic Aortic Grafts

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    Olivé Milián, ArmandPla general picat del mosaic format per tres cercles: el central, amb un sol de color ocre sobre un cel blau. El sol, somrient, està encarat cap al sud. Aquest està envoltat d'un primer anell dentat i un segon on s'hi representen les fases d

    Temperature Dependence of Spin-Split Peaks in Transverse Electron Focusing

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    We present experimental results of transverse electron-focusing measurements performed using n-type GaAs. In the presence of a small transverse magnetic field (B⊥), electrons are focused from the injector to detector leading to focusing peaks periodic in B⊥. We show that the odd-focusing peaks exhibit a split, where each sub-peak represents a population of a particular spin branch emanating from the injector. The temperature dependence reveals that the peak splitting is well defined at low temperature whereas it smears out at high temperature indicating the exchange-driven spin polarisation in the injector is dominant at low temperatures
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