Ab initio simulations of liquid systems: Concentration dependence of the electric conductivity of NaSn alloys

Liquid NaSn alloys in five different compositions (20, 40, 50, 57 and 80% sodium) are studied using density functional calculations combined with molecular dynamics(Car-Parrinello method). The frequency-dependent electric conductivities for the systems are calculated by means of the Kubo-Greenwood formula. The extrapolated DC conductivities are in good agreement with the experimental data and reproduce the strong variation with the concentration. The maximum of conductivity is obtained, in agreement with experiment, near the equimolar composition. The strong variation of conductivity, ranging from almost semiconducting up to metallic behaviour, can be understood by an analysis of the densities-of-states.Comment: LaTex 6 pages and 2 figures, to appear in J.Phys. Cond. Ma

SLICC/ACR DAMAGE INDEX IS VALID, AND RENAL AND PULMONARY ORGAN SCORES ARE PREDICTORS OF SEVERE OUTCOME IN PATIENTS WITH SYSTEMIC LUPUS ERYTHEMATOSUS

We investigated the Systemic Lupus International Collaborative Clinics/American College of Rheumatology (SLICC/ACR) Damage Index as a predictor of severe outcome and an indicator of morbidity in different ethnic groups, and in regard to its validity. We retrospectively studied disease course within 10 yr of diagnosis in an inception cohort of 80 patients with systemic lupus erythematosus (SLE). The mean renal damage score (DS) at 1 yr after diagnosis was a significant predictor of endstage renal failure and the mean pulmonary DS at 1 yr significantly predicted death within 10 yr of diagnosis. Compared to Caucasians, Afro-Caribbeans and Asians had significantly higher mean total DS at 5 and 10 yr, and higher mean renal DS at 10 yr. At 5 yr, the mean renal DS in Afro-Caribbeans and the mean neuropsychiatric DS in Asians were significantly higher than in Caucasians. The rate of endstage renal failure in Caucasians was significantly lower than in the other ethnic groups. Our results confirm the validity of the SLICC/ACR Damage Inde

Mobility and Diffusion of a Tagged Particle in a Driven Colloidal Suspension

We study numerically the influence of density and strain rate on the diffusion and mobility of a single tagged particle in a sheared colloidal suspension. We determine independently the time-dependent velocity autocorrelation functions and, through a novel method, the response functions with respect to a small force. While both the diffusion coefficient and the mobility depend on the strain rate the latter exhibits a rather weak dependency. Somewhat surprisingly, we find that the initial decay of response and correlation functions coincide, allowing for an interpretation in terms of an 'effective temperature'. Such a phenomenological effective temperature recovers the Einstein relation in nonequilibrium. We show that our data is well described by two expansions to lowest order in the strain rate.Comment: submitted to EP

First measurements of the flux integral with the NIST-4 watt balance

In early 2014, construction of a new watt balance, named NIST-4, has started at the National Institute of Standards and Technology (NIST). In a watt balance, the gravitational force of an unknown mass is compensated by an electromagnetic force produced by a coil in a magnet system. The electromagnetic force depends on the current in the coil and the magnetic flux integral. Most watt balances feature an additional calibration mode, referred to as velocity mode, which allows one to measure the magnetic flux integral to high precision. In this article we describe first measurements of the flux integral in the new watt balance. We introduce measurement and data analysis techniques to assess the quality of the measurements and the adverse effects of vibrations on the instrument.Comment: 7 pages, 8 figures, accepted for publication in IEEE Trans. Instrum. Meas. This Journal can be found online at http://ieeexplore.ieee.org/xpl/RecentIssue.jsp?punumber=1

Outcome of patients admitted with acute coronary syndrome on palliative treatment: insights from the nationwide AMIS Plus Registry 1997-2014.

OBJECTIVE: Compliance with guidelines is increasingly used to benchmark the quality of hospital care, however, very little is known on patients admitted with acute coronary syndromes (ACS) and treated palliatively. This study aimed to evaluate the baseline characteristics and outcomes of these patients. DESIGN: Prospective cohort study. SETTING: Eighty-two Swiss hospitals enrolled patients from 1997 to 2014. PARTICIPANTS: All patients with ACS enrolled in the AMIS Plus registry (n=45,091) were analysed according to three treatment groups: palliative treatment, defined as use of aspirin and analgesics only and no reperfusion; conservative treatment, defined as any treatment including antithrombotics or anticoagulants, heparins, P2Y12 inhibitors, GPIIb/IIIa but no pharmacological or mechanical reperfusion; and reperfusion treatment (thrombolysis and/or percutaneous coronary intervention during initial hospitalisation). The primary outcome measure was in-hospital mortality and the secondary measure was 1-year mortality. RESULTS: Of the patients, 1485 (3.3%) were palliatively treated, 11,119 (24.7%) were conservatively treated and 32,487 (72.0%) underwent reperfusion therapy. In 1997, 6% of all patients were treated palliatively and this continuously decreased to 2% in 2013. Baseline characteristics of palliative patients differed in comparison with conservatively treated and reperfusion patients in age, gender and comorbidities (all p<0.001). These patients had more in-hospital complications such as postadmission onset of cardiogenic shock (15.6% vs 5.2%; p<0.001), stroke (1.8% vs 0.8%; p=0.001) and a higher in-hospital mortality (25.8% vs 5.6%; p<0.001).The subgroup of patients followed 1 year after discharge (n=8316) had a higher rate of reinfarction (9.2% vs 3.4%; p=0.003) and mortality (14.0% vs 3.5%; p<0.001). CONCLUSIONS: Patients with ACS treated palliatively were older, sicker, with more heart failure at admission and very high in-hospital mortality. While refraining from more active therapy may often constitute the most humane and appropriate approach, we think it is important to also evaluate these patients and include them in registries and outcome evaluations. CLINICAL TRIAL NUMBER: ClinicalTrials.gov Identifier: NCT01 305 785

TGRS Observations of Positron Annihilation in Classical Novae

The TGRS experiment on board the Wind spacecraft has many advantages as a sky monitor --- broad field of view (~2 pi) centered on the south ecliptic pole), long life (1994-present), and stable low background and continuous coverage due to Wind's high altitude high eccentricity orbit. The Ge detector has sufficient energy resolution (3-4 keV at 511 keV) to resolve a cosmic positron annihilation line from the strong background annihilation line from beta-decays induced by cosmic ray impacts on the instrument, if the cosmic line is Doppler-shifted by this amount. Such lines (blueshifted) are predicted from nucleosynthesis in classical novae. We have searched the entire TGRS database for 1995-1997 for this line, with negative results. In principle such a search could yield an unbiased upper limit on the highly-uncertain Galactic nova rate. We carefully examined the times around the known nova events during this period, also with negative results. The upper limit on the nova line flux in a 6-hr interval is typically <3.8 E-3 photon/(cm2 s) at 4.6 sigma. We performed the same analysis for times around the outburst of Nova Vel 1999, obtaining a worse limit due to recent degradation of the detector response caused by cosmic ray induced damage.Comment: 5 pp. inc. 3 figs. Proc. 5th Compton Symposium (AIP Conf. Series), ed. M. McConnell, in pres

Stresses in lipid membranes

The stresses in a closed lipid membrane described by the Helfrich hamiltonian, quadratic in the extrinsic curvature, are identified using Noether's theorem. Three equations describe the conservation of the stress tensor: the normal projection is identified as the shape equation describing equilibrium configurations; the tangential projections are consistency conditions on the stresses which capture the fluid character of such membranes. The corresponding torque tensor is also identified. The use of the stress tensor as a basis for perturbation theory is discussed. The conservation laws are cast in terms of the forces and torques on closed curves. As an application, the first integral of the shape equation for axially symmetric configurations is derived by examining the forces which are balanced along circles of constant latitude.Comment: 16 pages, introduction rewritten, other minor changes, new references added, version to appear in Journal of Physics

Changes in axonal excitability of primary sensory afferents with general anaesthesia in humans

Background Intraoperative monitoring of neuronal function is important in a variety of surgeries. The type of general anaesthetic used can affect the interpretation and quality of such recordings. Although the principal effects of general anaesthetics are synaptically mediated, the extent to which they affect excitability of the peripheral afferent nervous system is unclear. Methods Forty subjects were randomized in a stratified manner into two groups, anaesthetized with either propofol or sevoflurane. The threshold tracking technique (QTRAC®) was used to measure nerve excitability parameters of the sensory action potential of the median nerve before and after induction of general anaesthesia. Results Several parameters of peripheral sensory afferent nerve excitability changed after induction of general anaesthesia, which were similar for both propofol and sevoflurane. The maximum amplitude of the sensory nerve action potential decreased in both groups (propofol: 25.3%; sevoflurane: 29.5%; both P<0.01). The relative refractory period [mean (sd)] also decreased similarly in both groups [propofol: −0.6 (0.7) ms; sevoflurane: −0.3 (0.5) ms; both P<0.01]. Skin temperature at the stimulation site increased significantly in both groups [propofol: +1.2 (1.0)°C; sevoflurane: +1.7 (1.4)°C; both P<0.01]. Conclusions Small changes in excitability of primary sensory afferents after the induction of anaesthesia with propofol or sevoflurane were detected. These effects, which were non-specific and are possibly explained by changes observed in temperature, demonstrate possible anaesthetic effects on intraoperative neuromonitorin