Non-commutative oscillator with Kepler-type dynamical symmetry

A 3-dimensional non-commutative oscillator with no mass term but with a certain momentum-dependent potential admits a conserved Runge-Lenz vector, derived from the dual description in momentum space. The latter corresponds to a Dirac monopole with a fine-tuned inverse-square plus Newtonian potential, introduced by McIntosh, Cisneros, and by Zwanziger some time ago. The trajectories are (arcs of) ellipses, which, in the commutative limit, reduce to the circular hodographs of the Kepler problem. The dynamical symmetry allows for an algebraic determination of the bound-state spectrum and actually extends to the conformal algebra o(4,2).Comment: 10 pages, 3 figures. Published versio

Comparison of two devices for automated oxygen control in preterm infants: a randomised crossover trial

Objective To compare the effect of two different automated oxygen control devices on target range (TR) time and occurrence of hypoxaemic and hyperoxaemic episodes.Design Randomised cross-over study.Setting Tertiary level neonatal unit in the Netherlands.Patients Preterm infants (n=15) born between 24+0 and 29+6 days of gestation, receiving invasive or non-invasive respiratory support with oxygen saturation (SpO(2)) TR of 91%-95%. Median gestational age 26 weeks and 4 days (IQR 25 weeks 3days-27 weeks 6 days) and postnatal age 19 (IQR 17-24) days.Interventions Inspired oxygen concentration was titrated by the OxyGenie controller (SLE6000 ventilator) and the CLIO2 controller (AVEA ventilator) for 24 hours each, in a random sequence, with the respiratory support mode kept constant.Main outcome measures Time spent within set SpO(2) TR (91%-95% with supplemental oxygen and 91%-100% without supplemental oxygen).Results Time spent within the SpO(2) TR was higher during OxyGenie control (80.2 (72.6-82.4)% vs 68.5 (56.7-79.3)%, p<0.005). Less time was spent above TR while in supplemental oxygen (6.3 (5.1-9.9)% vs 15.9 (11.5-30.7)%, p<0.005) but more time spent below TR during OxyGenie control (14.7 (11.8%-17.2%) vs 9.3 (8.2-12.6)%, p<0.05). There was no significant difference in time with SpO(2) <80% (0.5 (0.1-1.0)% vs 0.2 (0.1-0.4)%, p=0.061). Long-lasting SpO(2) deviations occurred less frequently during OxyGenie control.Conclusions The OxyGenie control algorithm was more effective in keeping the oxygen saturation within TR and preventing hyperoxaemia and equally effective in preventing hypoxaemia (SpO(2) <80%), although at the cost of a small increase in mild hypoxaemia.Developmen

Photomodulation of transmembrane transport and potential by stiff-stilbene based bis(thio)ureas

NWOSupramolecular & Biomaterials Chemistr

An efficient algorithm to calculate intrinsic thermoelectric parameters based on Landauer approach

The Landauer approach provides a conceptually simple way to calculate the intrinsic thermoelectric (TE) parameters of materials from the ballistic to the diffusive transport regime. This method relies on the calculation of the number of propagating modes and the scattering rate for each mode. The modes are calculated from the energy dispersion (E(k)) of the materials which require heavy computation and often supply energy relation on sparse momentum (k) grids. Here an efficient method to calculate the distribution of modes (DOM) from a given E(k) relationship is presented. The main features of this algorithm are, (i) its ability to work on sparse dispersion data, and (ii) creation of an energy grid for the DOM that is almost independent of the dispersion data therefore allowing for efficient and fast calculation of TE parameters. The inclusion of scattering effects is also straight forward. The effect of k-grid sparsity on the compute time for DOM and on the sensitivity of the calculated TE results are provided. The algorithm calculates the TE parameters within 5% accuracy when the K-grid sparsity is increased up to 60% for all the dimensions (3D, 2D and 1D). The time taken for the DOM calculation is strongly influenced by the transverse K density (K perpendicular to transport direction) but is almost independent of the transport K density (along the transport direction). The DOM and TE results from the algorithm are bench-marked with, (i) analytical calculations for parabolic bands, and (ii) realistic electronic and phonon results for $Bi_{2}Te_{3}$.Comment: 16 Figures, 3 Tables, submitted to Journal of Computational electronic

The ALSFRS-R Summit: a global call to action on the use of the ALSFRS-R in ALS clinical trials

The Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS) was developed more than 25 years ago as an instrument to monitor functional change over time in patients with ALS. It has since been revised and extended to meet the needs of high data quality in ALS trials (ALSFRS-R), however a full re-validation of the scale was not completed. Despite this, the scale has remained a primary outcome measure in clinical trials. We convened a group of clinical trialists to discuss and explore opportunities to improve the scale and propose alternative measures. In this meeting report, we present a call to action on the use of the ALSFRS-Revised scale in clinical trials, focusing on the need for (1) harmonization of the ALSFRS-R administration globally, (2) alignment on a set of recommendations for clinical trial design and statistical analysis plans (SAPs), and (3) use of additional outcome measures

Anion coordination and anion-templated assembly: Highlights from 2002 to 2004

This review article highlights advances made in abiotic anion coordination chemistry from 2002 to 2004. The structure of this review is that similar to the previous reviews in this series that covered 1997-2001 [P.A. Gale, Coord. Chem. Rev. 199 (2000) 181; P.A. Gale, Coord. Chem. Rev. 213 (2001) 79; P.A. Gale, Coord. Chem. Rev. 240 (2003) 191]. The first section examines anion receptors that do not contain metal ions. This is followed by a review of metal containing anion receptors and finally the role of anions in directing the self-assembly of complex molecular architectures are presented in the final section

Approach to the fracture hydrology at Stripa: preliminary results

There are two main problems associated with the concept of geologic storage of radioactive waste in fractured crystalline rock: (1) the thermo-mechanical effects of the heat generated by the waste, and (2) the potential for transport of radioactive materials by the groundwater system. In both problems, fractures play a dominant role. An assessment of the hydraulic and mechanical characteristics of fractued rock requires a careful series of laboratory and field investigations. The complexity of the problem is illustrated by the field studies in a fractured granite that are currently underway in an abandoned iron-ore mine at Stripa, Sweden. Much information is being gathered from an extensive series of boreholes and fracture maps. The approach being taken to integrate these data into an analysis of the fracture hydrology is reviewed and preliminary results from the hydrology program are presented. 13 figures

Waste disposal in granite: preliminary results from Stripa, Sweden

The results of this experiment to date indicate that the temperature fields in a rock mass contaning geologic discontinuities can be predicted with accuracy using the simple linear theory of heat conduction. Geologic discontinuities appear to introduce significant non-linear thermomechanical behavior into the rock mass as a result of which the thermally induced displacements are much less than those predicted by the simple theory of thermoelasticity, using laboratory values for Poisson's ratio and the coefficient of thermal expansion. The additional compliance introduced into the rock mass by geologic discontinuities affects the thermally induced stresses but to a lesser degree than the displacements. Further analytical, laboratory and field studies are expected to resolve many of the current uncertainties, especially field data gathered during a planned cooling down period following the switching off of the heaters scheduled in the near future