439 research outputs found

    Tracking and Improving Bedside Procedures Through Standardized Documentation

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    Proposal and Goals: We propose to create a standardized electronic procedure note that will replace all documentation for bedside procedures without sedation. ◦Makes notes legible and easily identified ◦Allows uniform tracking of metrics necessary to identify outcomes from a procedure (blood loss, specimens, post-procedure studies, complications) 2.The procedure note will be created in such a way as to allow specialized procedures to be added over time with minor customization to improve physician/nursing work flows and increase efficiency ◦Allows procedures to be sorted and tracked by type ◦Will be constructed to allow attaching CPT codes to patient charts via documentation 3. We propose using this procedure note to create a running database of all bedside procedures ◦Can be utilized by existing software (Qlik) to query all procedure notes to create large anonymized patient listshttps://jdc.jefferson.edu/patientsafetyposters/1071/thumbnail.jp

    Filling the Void: A Low Cost, High-Yield Method to Addressing Incidental Findings in Trauma Patients

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    In this study we: Report the incidence of incidental findings in a suburban trauma center treating primarily blunt and elderly trauma Propose simple solutions to increase the rate of disclosure to patientshttps://jdc.jefferson.edu/patientsafetyposters/1070/thumbnail.jp

    Studies of superconducting materials with muon spin rotation

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    The muon spin rotation/relaxation technique was found to be an exceptionally effective means of measuring the magnetic properties of superconductors, including the new high temperature superconductor materials, at the microscopic level. The technique directly measures the magnetic penetration depth (type II superconductors (SC's)) and detects the presence of magnetic ordering (antiferromagnetism or spin-glass ordering were observed in some high temperature superconductor (HTSC's) and in many closely related compounds). Extensive studies of HTSC materials were conducted by the Virginia State University - College of William and Mary - Columbia University collaboration at Brookhaven National Laboratory and TRIUMF (Vancouver). A survey of LaSrCuO and YBaCaCuO systems shows an essentially linear relationship between the transition temperature T(sub c) and the relaxation rate. This appears to be a manifestation of the proportionality between T(sub c) and the Fermi energy, which suggests a high energy scale for the SC coupling, and which is not consistent with the weak coupling of phonon-mediated SC. Studies of LaCuO and YBaCuO parent compounds show clear evidence of antiferromagnetism. YBa2Cu(3-x)CO(x)O7 shows the simultaneous presence of spin-glass magnetic ordering and superconductivity. Three-dimensional SC, (Ba, K) BiO3, unlike the layered CuO-based compounds, shows no suggestion of magnetic ordering. Experimental techniques and theoretical implications are discussed

    Superconducting Order Parameter in Bi-Layer Cuprates: Occurrence of π\pi Phase Shifts in Corner Junctions

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    We study the order parameter symmetry in bi-layer cuprates such as YBaCuO, where interesting π\pi phase shifts have been observed in Josephson junctions. Taking models which represent the measured spin fluctuation spectra of this cuprate, as well as more general models of Coulomb correlation effects, we classify the allowed symmetries and determine their associated physical properties. π\pi phase shifts are shown to be a general consequence of repulsive interactions, independent of whether a magnetic mechanism is operative. While it is known to occur in d-states, this behavior can also be associated with (orthorhombic) s-symmetry when the two sub-band gaps have opposite phase. Implications for the magnitude of TcT_c are discussed.Comment: 5 pages, RevTeX 3.0, 9 figures (available upon request

    Antiferromagnetic Excitations and Van Hove Singularities in YBa2_2Cu3_3O6+x_{6+x}

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    We show that in quasi-two-dimensional dd-wave superconductors Van Hove singularities close to the Fermi surface lead to novel magnetic quasi-particle excitations. We calculate the temperature and doping dependence of dynamical magnetic susceptibility for YBCO and show that the proposed excitations are in agreement with inelastic neutron scattering experiments. In addition, the values of the gap parameter and in-plane antiferromagnetic coupling are much smaller than usually believed.Comment: REVTeX, 4 pages + 3 PostScript (compressed) figures; to appear in Phys. Rev. B (Rap. Comm.

    Pressure Effects in Manganites with Layered Perovskite Structure

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    Pressure effects on the charge and spin dynamics in the bilayer manganite compounds La22xSr1+2xMn2O7La_{2-2x}Sr_{1+2x}Mn_2O_7 are studied theoretically by taking into account the orbital degrees of freedom. The orbital degrees are active in the layered crystal structure, and applied hydrostatic pressure stabilizes the 3dx2y23d_{x^2-y^2} orbital in comparison with 3d3z2r23d_{3z^2-r^2}. The change of the orbital states weakens the interlayer charge and spin couplings, and suppresses the three dimensional ferromagnetic transition. Numerical results, based on an effective Hamiltonian which includes the energy level difference of the orbitals, show that the applied pressure controls the dimensionality of the spin and charge dynamics through changes of the orbital states.Comment: 5 pages, 2 figure

    On the Magnetic Excitation Spectra of High Tc Cu Oxides up to the Energies far above the Resonance Energy

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    Magnetic excitation spectra c"(q,w) of YBa2Cu3Oy and La214 systems have been studied. For La1.88Sr0.12CuO4, c"(q,w) have been measured up to ~30 meV and existing data have been analyzed up to the energy w~150 meV by using the phenomenological expression of the generalized magnetic susceptibility c(q,w)=c0(q,w)/{1+J(q)c0(q,w)}, where c0(q,w) is the susceptibility of the electrons without the exchange coupling J(q) among them. In the relatively low energy region up to slightly above the resonance energy Er, it has been reported by the authors' group that the expression can explain characteristics of the q- and w-dependence of the spectra of YBa2Cu3Oy (YBCO or YBCOy). Here, it is also pointed out that the expression can reproduce the rotation of four incommensurate peaks of c"(q,w) within the a*-b* plane about (p/a, p/a) {or so-called (p, p)} point by 45 degree, which occurs as w goes to the energy region far above Er from E below Er. For La2-xSrxCuO4 and La2-xBaxCuO4, agreements between the observed results and the calculations are less satisfactory than for YBCO, indicating that we have to take account of the existence of the "stripes" to consistently explain the observed c"(q,w) of La214 system especially near x=1/8.Comment: 14 pages, 5 figure

    Interplay of the CE-type charge ordering and the A-type spin ordering in a half-doped bilayer manganite La{1}Sr{2}Mn{2}O{7}

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    We demonstrate that the half-doped bilayer manganite La_{1}Sr_{2}Mn_{2}O_{7} exhibits CE-type charge-ordered and spin-ordered states below TN,COA=210T_{N, CO}^A = 210 K and below TNCE145T_{N}^{CE} \sim 145 K, respectively. However, the volume fraction of the CE-type ordering is relatively small, and the system is dominated by the A-type spin ordering. The coexistence of the two types of ordering is essential to understand its transport properties, and we argue that it can be viewed as an effective phase separation between the metallic d(x2y2)d(x^{2}-y^{2}) orbital ordering and the charge-localized d(3x2r2)/d(3y2r2)d(3x^{2}-r^{2})/d(3y^{2}-r^{2}) orbital ordering.Comment: 5 pages, 4 figures, submitted to Phys. Rev.

    Stripe order, depinning, and fluctuations in La1.875_{1.875}Ba0.125_{0.125}CuO4_{4} and La1.875_{1.875}Ba0.075_{0.075}Sr0.050_{0.050}CuO4_{4}

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    We present a neutron scattering study of stripe correlations measured on a single crystal of La1.875_{1.875}Ba0.125_{0.125}CuO4_{4}. Within the low-temperature-tetragonal (LTT) phase, superlattice peaks indicative of spin and charge stripe order are observed below 50 K. For excitation energies ω12\hbar\omega\le12 meV, we have characterized the magnetic excitations that emerge from the incommensurate magnetic superlattice peaks. In the ordered state, these excitations are similar to spin waves. Following these excitations as a function of temperature, we find that there is relatively little change in the {\bf Q}-integrated dynamical spin susceptibility for ω10\hbar\omega\sim10 meV as stripe order disappears and then as the structure transforms from LTT to the low-temperature-orthorhombic (LTO) phase. The {\bf Q}-integrated signal at lower energies changes more dramatically through these transitions, as it must in a transformation from an ordered to a disordered state. We argue that the continuous evolution through the transitions provides direct evidence that the incommensurate spin excitations in the disordered state are an indicator of dynamical charge stripes. An interesting feature of the thermal evolution is a variation in the incommensurability of the magnetic scattering. Similar behavior is observed in measurements on a single crystal of La1.875_{1.875}Ba0.075_{0.075}Sr0.050_{0.050}CuO4_{4}; maps of the scattered intensity in a region centered on the antiferromagnetic wave vector and measured at ω=4\hbar\omega=4 meV are well reproduced by a model of disordered stripes with a temperature-dependent mixture of stripe spacings. We discuss the relevance of our results to understanding the magnetic excitations in cuprate superconductors.Comment: 12 pages, 11 figures, 1 tabl

    Anomalous Spin Dynamics in Doped Quantum Antiferromagnets

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    Finite-temperature spin dynamics in planar t-J model is studied using the method based on the Lanczos diagonalization of small systems. Dynamical spin structure factor at moderate dopings shows the coexistence of free-fermion-like and spin-fluctuation timescales. At T<J, the low-frequency and static susceptibility show pronounced T dependence, supporting a scenario, related to the marginal Fermi-liquid one, for the explanation of neutron-scattering and NMR-relaxation experiments in cuprates. Calculated NMR relaxation rates reasonably reproduce experimental ones.Comment: 10 pages + 4 figures, Postscript in uuencoded compressed tar file, IJS-TP-94/2
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