18,866 research outputs found

    Intertwined Orders in Heavy-Fermion Superconductor CeCoIn5_5

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    The appearance of spin-density-wave (SDW) magnetic order in the low-temperature and high-field corner of the superconducting phase diagram of CeCoIn5_5 is unique among unconventional superconductors. The nature of this magnetic QQ phase is a matter of current debate. Here, we present the thermal conductivity of CeCoIn5_5 in a rotating magnetic field, which reveals the presence of an additional order inside the QQ phase that is intimately intertwined with the superconducting dd-wave and SDW orders. A discontinuous change of the thermal conductivity within the QQ phase, when the magnetic field is rotated about antinodes of the superconducting dd-wave order parameter, demands that the additional order must change abruptly together with the recently observed switching of the SDW. A combination of interactions, where spin-orbit coupling orients the SDW, which then selects the secondary pp-wave pair-density-wave component (with an average amplitude of 20\% of the primary dd-wave order parameter), accounts for the observed behavior

    High pressure investigation of the heavy-fermion antiferromagnet U_3Ni_5Al_19

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    Measurements of magnetic susceptibility, specific heat, and electrical resistivity at applied pressures up to 55 kbar have been carried out on single crystals of the heavy-fermion antiferromagnet U_3Ni_5Al_19, which crystallizes in the Gd_3Ni_5Al_19 orthorhombic structure with two inequivalent U sites. At ambient pressure, a logarithmic T-dependence of the specific heat and T-linear electrical resistivity below 5 K indicates non-Fermi liquid (NFL) behavior in the presence of bulk antiferromagnetic order at T_N=23 K. Electrical resistivity measurements reveal a crossover from non-Fermi liquid to Fermi liquid behavior at intermediate pressures between 46 kbar and 51 kbar, followed by a return to NFL T^{3/2} behavior at higher pressures. These results provide evidence for an ambient pressure quantum critical point and an additional antiferromagnetic instability at P_c=60 kbar.Comment: 12 pages, 5 figure

    Preventative tele-health supported services for early stage chronic obstructive pulmonary disease: a protocol for a pragmatic randomized controlled trial pilot

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    Background Chronic Obstructive Pulmonary Disease (COPD) is a prevalent debilitating long term condition. It is the second most common cause of emergency admission to hospital in the UK and remains one of the most costly conditions to treat through acute care. Tele-health monitoring offers potential to reduce the rates of re-hospitalisation and emergency department visits and improve quality of life for people with COPD. However, the current evidence base to support technology adoption and implementation is limited and the resource implications for implementing tele-health in practice can be very high. This trial will employ tele-health monitoring in a preventative capacity for patients diagnosed with early stage COPD following discharge from hospital to determine whether it reduces their need for additional health service support or hospital admission and improves their quality of life. Methods/Design We describe a pilot study for a two arm, one site randomized controlled trial (RCT) to determine the effect of tele-health monitoring on self-management, quality of life and patient satisfaction. Sixty patients who have been discharged from one acute trust with a primary diagnosis of COPD and who have agreed to receive community clinical support following discharge from acute care will be randomly assigned to one of two groups: (a) Tele-health supported Community COPD Service; or (b) Usual Care. The tele-health supported service involves the patient receiving two home visits with a specialist COPD clinician (nurse or physiotherapist) then participating in daily tele-monitoring over an eight week period. Usual care consists of six home visits to the patient by specialist COPD clinicians again over eight successive weeks. Health status and quality of life data for all participants will be measured at baseline, on discharge from the service and at six months post discharge from the service. Discussion The tele-health service under study is a complex service delivered through a collaboration between local authority and health care partners. The implementation of this service demanded significant changes to established working patterns and has been a challenging process requiring considerable planning - a challenge that many providers are likely to face in the future. Trial registration Current Controlled Trials ISRCTN6885601

    Effects of pressure on the ferromagnetic state of the CDW compound SmNiC2

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    We report the pressure response of charge-density-wave (CDW) and ferromagnetic (FM) phases of the rare-earth intermetallic SmNiC2 up to 5.5 GPa. The CDW transition temperature (T_{CDW}), which is reflected as a sharp inflection in the electrical resistivity, is almost independent of pressure up to 2.18 GPa but is strongly enhanced at higher pressures, increasing from 155.7 K at 2.2 GPa to 279.3 K at 5.5 GPa. Commensurate with the sharp increase in T_{CDW}, the first-order FM phase transition, which decreases with applied pressure, bifurcates into the upper (T_{M1}) and lower (T_c) phase transitions and the lower transition changes its nature to second order above 2.18 GPa. Enhancement both in the residual resistivity and the Fermi-liquid T^2 coefficient A near 3.8 GPa suggests abundant magnetic quantum fluctuations that arise from the possible presence of a FM quantum critical point.Comment: 5 pages, 5 figure

    Identification of aquatic mycobacteria based on sequence analysis of the 16S-23S rRNA internal transcribed spacer region

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    Purpose. Mycobacteria are common causative agents of bacterial infections in many species of freshwater and marine fish. Identification of mycobacteria to the species level based on phenotypic tests is inappropriate and time consuming. Molecular methods such as partial or entire gene sequence determination in mycobacteria have been employed to resolve these problems. The objective of this study was to assess the use of sequence analysis of the mycobacterial 16S–23S internal transcribed spacer (ITS) region for the identification of different aquatic mycobacteria species. Methodology. Using published primers, the ITS sequences of 64 field and reference strains were determined. Results/Key findings. The identity of all isolates previously identified as Mycobacterium marinum by RFLP was confirmed as M. marinum by sequence analysis. With the exception of five rapidly growing mycobacteria isolates, all other mycobacteria were easily identified by sequencing of the ITS region. Using this spacer region, it was possible to differentiate between slowly growing and rapidly growing mycobacteria, even before sequence analysis, by the size of the PCR product, although species identification could not be made by size alone. Conclusion. Overall, direct sequencing of this genetic element following PCR has been shown to be useful in the identification of aquatic mycobacteria species. With regard to the variability of the ITS region for different mycobacteria isolates, this may be a useful tool in epidemiological studies

    Large magnetic penetration depth and thermal fluctuations in a Ca10_{10}(Pt3_{3}As8_{8})[(Fe1x_{1-x}Ptx_{x})2_{2}As2_{2}]5_{5} (x=0.097) single crystal

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    We have measured the temperature dependence of the absolute value of the magnetic penetration depth λ(T)\lambda(T) in a Ca10_{10}(Pt3_{3}As8_{8})[(Fe1x_{1-x}Ptx_{x})2_{2}As2_{2}]5_{5} (x=0.097) single crystal using a low-temperature magnetic force microscope (MFM). We obtain λab\lambda_{ab}(0)\approx1000 nm via extrapolating the data to T=0T = 0. This large λ\lambda and pronounced anisotropy in this system are responsible for large thermal fluctuations and the presence of a liquid vortex phase in this low-temperature superconductor with critical temperature of 11 K, consistent with the interpretation of the electrical transport data. The superconducting parameters obtained from λ\lambda and coherence length ξ\xi place this compound in the extreme type \MakeUppercase{\romannumeral 2} regime. Meissner responses (via MFM) at different locations across the sample are similar to each other, indicating good homogeneity of the superconducting state on a sub-micron scale
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