Quasiparticles in the Pseudogap Phase of Underdoped Cuprate

Recent angle resolved photoemission \cite{yang-nature-08} and scanning tunneling microscopy \cite{kohsaka-nature-08} measurements on underdoped cuprates have yielded new spectroscopic information on quasiparticles in the pseudogap phase. New features of the normal state such as particle-hole asymmetry, maxima in the energy dispersion and accompanying drops in the spectral weight of quasiparticles agree with the ansatz of Yang \textit{et al.} for the single particle propagator in the pseudogap phase. The coherent quasiparticle dispersion and reduced asymmetry in the tunneling density of states in the superconducting state can also be described by this propagator.Comment: updated version, 6 pages, 7 figures, 1 table, EPL 86 (2009) 37002 (https://www.epletters.net

Magnetism and superconductivity in underscreened Kondo chains

We present a one dimensional model of electrons coupled to localized moments of spin $S\ge 1$ in which magnetism and superconductivity interplay in a nontrivial manner. This model has a non-Fermi liquid ground state of the chiral spin liquid type. A non-conventional odd-frequency pairing is shown to be the dominant instability of the system, together with antiferromagnetism of the local moments. We argue that this model captures the physics of the Kondo-Heisenberg spin S=1 chain, in the limit of strong Kondo coupling. Finally, we discuss briefly the effect of interchain coupling.Comment: no figures, 4 two column pages, Revte

Obstructed defaecation syndrome: European consensus guidelines on the surgical management.

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Chiral superconductivity from repulsive interactions in doped graphene

Author Manuscript 17 Sep 2011Chiral superconductivity, which breaks time-reversal symmetry, can exhibit a wealth of fascinating properties that are highly sought after for nanoscience applications. We identify doped graphene monolayer as a system where chiral superconductivity can be realized. In this material, a unique situation arises at a doping where the Fermi surface is nested and the density of states is singular. In this regime, d-wave superconductivity can emerge from repulsive electron–electron interactions. Using a renormalization group method, we argue that superconductivity dominates over all competing orders for generic weak repulsive interactions. Superconductivity develops simultaneously in two degenerate d-wave pairing channels. We argue that the resulting superconducting state is of chiral type, with the phase of the superconducting order parameter winding by 4π around the Fermi surface. Realization of this state in doped graphene will prove that superconductivity can emerge from electron–electron repulsion, and will open the door to applications of chiral superconductivity

Global patient outcomes after elective surgery: prospective cohort study in 27 low-, middle- and high-income countries.

BACKGROUND: As global initiatives increase patient access to surgical treatments, there remains a need to understand the adverse effects of surgery and define appropriate levels of perioperative care. METHODS: We designed a prospective international 7-day cohort study of outcomes following elective adult inpatient surgery in 27 countries. The primary outcome was in-hospital complications. Secondary outcomes were death following a complication (failure to rescue) and death in hospital. Process measures were admission to critical care immediately after surgery or to treat a complication and duration of hospital stay. A single definition of critical care was used for all countries. RESULTS: A total of 474 hospitals in 19 high-, 7 middle- and 1 low-income country were included in the primary analysis. Data included 44 814 patients with a median hospital stay of 4 (range 2-7) days. A total of 7508 patients (16.8%) developed one or more postoperative complication and 207 died (0.5%). The overall mortality among patients who developed complications was 2.8%. Mortality following complications ranged from 2.4% for pulmonary embolism to 43.9% for cardiac arrest. A total of 4360 (9.7%) patients were admitted to a critical care unit as routine immediately after surgery, of whom 2198 (50.4%) developed a complication, with 105 (2.4%) deaths. A total of 1233 patients (16.4%) were admitted to a critical care unit to treat complications, with 119 (9.7%) deaths. Despite lower baseline risk, outcomes were similar in low- and middle-income compared with high-income countries. CONCLUSIONS: Poor patient outcomes are common after inpatient surgery. Global initiatives to increase access to surgical treatments should also address the need for safe perioperative care. STUDY REGISTRATION: ISRCTN5181700

Fluctuation conductivity due to the preformed local pairs

We investigated the properties of a system where the itinerant electrons coexist and interact with the preformed local pairs. Using the nonperturbative continuous unitary transformation technique we show that Andreev-type scattering between these charge carriers gives rise to the enhanced diamagnetic response and is accompanied by appearance of the Drude peak inside the pseudogap regime ω ≤ 2Δpg . Both effects are caused by the short-range superconducting correlations above the transition temperature Tc. In fact, the residual diamagnetism has been detected by the torque magnetometry in the lanthanum and bismuth cuprate superconductors at temperatures up to ~1.5 T c. In this work we show how the superconducting correlations can be observed in the ac and dc conductivity. Remove selecte

Innovative appliance for colostomy patients: an interventional prospective pilot study

International audienceBackground The control of body waste emptying is a constant research topic in stoma care. The aim of this pilot study was to assess the efficacy and safety of an innovative colostomy appliance. Methods An interventional prospective non-comparative pilot study was conducted in seven French centers. The study device is a new type of two-piece appliance including a base plate and a ``capsule cap'' (CC) composed of a capsule cover and a folded collecting bag. The device gently seals the stoma to provide stoma output control. When the bowel movement pressure increases the patient may control the deployment of the folded bag and collect stools. Patients with left-sided colostomy all using a flat appliance, were enrolled in a 2-week trial. Outcome measures were type of CC removal and peristomal fecal leaks while wearing the device. Results Of 30 patients (females 66.7%), with left-sided colostomy (permanent 76.7%), 23 (76.7%) completed the 2-week trial. A total of 472 CC changes were analyzed. Efficacy: of 404 (85.5%) CC changes reported in diaries, 302 (74.8%) were linked with stool and/or gas. In 244 (60.3%) changes, the patient controlled stoma bag deployment and it occurred with bowel emptying 301 (74.5%) times. No leaks around the appliance were observed in 400 (85.3%) changes. Safety: no serious adverse event occurred. Peristomal skin was not modified during the trial. Conclusions In the short term this new device has provided an increased control over bowel emptying at no risk in half of the trial population suggesting that an alternative approach to bag wearing is achievable

Surgery for constipation: systematic review and practice recommendations: Graded practice and future research recommendations

Aim: This manuscript forms the final of seven that address the surgical management of chronic constipation (CC) in adults. The content coalesces results from the five systematic reviews that precede it and of the European Consensus process to derive graded practice recommendations (GPR). Methods: Summary of review data, development of GPR and future research recommendations as outlined in detail in the ‘introduction and methods’ paper. Results: The overall quality of data in the five reviews was poor with 113/156(72.4%) of included studies providing only level IV evidence and only four included level I RCTs. Coalescence of data from the five procedural classes revealed that few firm conclusions could be drawn regarding procedural choice or patient selection: no single procedure dominated in addressing dynamic structural abnormalities of the anorectum and pelvic floor with each having similar overall efficacy. Of one hundred ‘prototype’ GPRs developed by the clinical guideline group, 85/100 were deemed ‘appropriate’ based on the independent scoring of a panel of 18 European experts and use of RAND-UCLA consensus methodology. The remaining 15 were all deemed uncertain. Future research recommendations included some potential RCTs but also a strong emphasis on delivery of large multinational high-quality prospective cohort studies. Conclusion: While the evidence base for surgery in CC is poor, the widespread European consensus for GPRs is encouraging. Professional bodies have the opportunity to build on this work by supporting the efforts of their membership to help convert the documented recommendations into clinical guidelines