262 research outputs found
Nodal Superconducting Order Parameter and Thermodynamic Phase Diagram of (TMTSF)2ClO4
The organic materials (TMTSF)2X are unique unconventional superconductors
with archetypal quasi-one-dimensional (Q1D) electronic structures. Here, based
on our comprehensive field-angle-resolved calorimetry of (TMTSF)2ClO4, we
succeeded in mapping the nodal gap structure for the first time in Q1D systems,
by discriminating between the Fermi wavevectors and Fermi velocities. In
addition, the thermodynamic phase diagrams of (TMTSF)2ClO4 for all principal
field directions are obtained. These findings, providing strong evidence of
nodal spin-singlet superconductivity, serves as solid bases for further
elucidation of anomalous superconducting phenomena in (TMTSF)2X.Comment: 7 pages, 7 figures, including Supplemental Information added at the
end of the manuscrip
Comparative study of the visual system of two psammophilic lizards (Scincus scincus & Eumeces schneideri)
peer reviewe
The metallic transport of (TMTSF)_2X organic conductors close to the superconducting phase
Comparing resistivity data of quasi-one dimensional superconductors
(TMTSF)_2PF_6 and (TMTSF)_2ClO_4 along the least conducting c*-axis and along
the high conductivity a -axis as a function of temperature and pressure, a low
temperature regime is observed in which a unique scattering time governs
transport along both directions of these anisotropic conductors. However, the
pressure dependence of the anisotropy implies a large pressure dependence of
the interlayer coupling. This is in agreement with the results of
first-principles DFT calculations implying methyl group hyperconjugation in the
TMTSF molecule. In this low temperature regime, both materials exhibit for rc a
temperature dependence aT + bT^2. Taking into account the strong pressure
dependence of the anisotropy, the T-linear rc is found to correlate with the
suppression of the superconducting Tc, in close analogy with ra data. This work
is revealing the domain of existence of the 3D coherent regime in the generic
(TMTSF)_2X phase diagram and provides further support for the correlation
between T-linear resistivity and superconductivity in non-conventional
superconductors
MESURES LAGRANGIENNES DE GOUTTES ÉVAPORANTES DANS UNE TURBULENCE HOMOGÈNE ISOTROPE PAR HOLOGRAPHIE NUMÉRIQUE
International audienceWe present an optical technique capable of measuring 3D trajectories and size evolution of a dilute flow of droplets dispersing in a high Reynolds number turbulence, from a Lagrangian point of view. The technique used is an in-line digital holographic set-up, with an original reconstruction algorithm based on an inverse-problem approach. The experiment has been performed with water and freon droplets in a locally well defined homogeneous, nearly isotropic, turbulence. This technique allows to visualise the thermal wakes behind the droplets which are tracked
Clinical Study Comparison of a Bayesian Network with a Logistic Regression Model to Forecast IgA Nephropathy
Models are increasingly used in clinical practice to improve the accuracy of diagnosis. The aim of our work was to compare a Bayesian network to logistic regression to forecast IgA nephropathy (IgAN) from simple clinical and biological criteria. Retrospectively, we pooled the results of all biopsies (n = 155) performed by nephrologists in a specialist clinical facility between 2002 and 2009. Two groups were constituted at random. The first subgroup was used to determine the parameters of the models adjusted to data by logistic regression or Bayesian network, and the second was used to compare the performances of the models using receiver operating characteristics (ROC) curves. IgAN was found (on pathology) in 44 patients. Areas under the ROC curves provided by both methods were highly significant but not different from each other. Based on the highest Youden indices, sensitivity reached (100% versus 67%) and specificity (73% versus 95%) using the Bayesian network and logistic regression, respectively. A Bayesian network is at least as efficient as logistic regression to estimate the probability of a patient suffering IgAN, using simple clinical and biological data obtained during consultation
Acute respiratory failure in kidney transplant recipients: a multicenter study
International audienceINTRODUCTION: Data on pulmonary complications in renal transplant recipients are scarce. The aim of this study was to evaluate acute respiratory failure (ARF) in renal transplant recipients. METHODS: We conducted a retrospective observational study in nine transplant centers of consecutive kidney transplant recipients admitted to the intensive care unit (ICU) for ARF from 2000 to 2008. RESULTS: Of 6,819 kidney transplant recipients, 452 (6.6%) required ICU admission, including 200 admitted for ARF. Fifteen (7.5%) of these patients had combined kidney-pancreas transplantations. The most common causes of ARF were bacterial pneumonia (35.5%), cardiogenic pulmonary edema (24.5%) and extrapulmonary acute respiratory distress syndrome (ARDS) (15.5%). Pneumocystis pneumonia occurred in 11.5% of patients. Mechanical ventilation was used in 93 patients (46.5%), vasopressors were used in 82 patients (41%) and dialysis was administered in 104 patients (52%). Both the in-hospital and 90-day mortality rates were 22.5%. Among the 155 day 90 survivors, 115 patients (74.2%) were dialysis-free, including 75 patients (65.2%) who recovered prior renal function. Factors independently associated with in-hospital mortality were shock at admission (odds ratio (OR) 8.70, 95% confidence interval (95% CI) 3.25 to 23.29), opportunistic fungal infection (OR 7.08, 95% CI 2.32 to 21.60) and bacterial infection (OR 2.53, 95% CI 1.07 to 5.96). Five factors were independently associated with day 90 dialysis-free survival: renal Sequential Organ Failure Assessment (SOFA) score on day 1 (OR 0.68/SOFA point, 95% CI 0.52 to 0.88), bacterial infection (OR 0.43, 95% CI 0.21 to 0.90), three or four quadrants involved on chest X-ray (OR 0.44, 95% CI 0.21 to 0.91), time from hospital to ICU admission (OR 0.98/day, 95% CI 0.95 to 0.99) and oxygen flow at admission (OR 0.93/liter, 95% CI 0.86 to 0.99). CONCLUSIONS: In kidney transplant recipients, ARF is associated with high mortality and graft loss rates. Increased Pneumocystis and bacterial prophylaxis might improve these outcomes. Early ICU admission might prevent graft loss
Linking people, places and products. A guide for promoting quality linked to geographical origin and sustainable geographical indications
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