Canonical lossless state-space systems: Staircase forms and the Schur algorithm

A new finite atlas of overlapping balanced canonical forms for multivariate discrete-time lossless systems is presented. The canonical forms have the property that the controllability matrix is positive upper triangular up to a suitable permutation of its columns. This is a generalization of a similar balanced canonical form for continuous-time lossless systems. It is shown that this atlas is in fact a finite sub-atlas of the infinite atlas of overlapping balanced canonical forms for lossless systems that is associated with the tangential Schur algorithm; such canonical forms satisfy certain interpolation conditions on a corresponding sequence of lossless transfer matrices. The connection between these balanced canonical forms for lossless systems and the tangential Schur algorithm for lossless systems is a generalization of the same connection in the SISO case that was noted before. The results are directly applicable to obtain a finite sub-atlas of multivariate input-normal canonical forms for stable linear systems of given fixed order, which is minimal in the sense that no chart can be left out of the atlas without losing the property that the atlas covers the manifold

Balanced realizations of discrete-time stable all-pass systems and the tangential Schur algorithm

In this paper, the connections are investigated between two different approaches towards the parametrization of multivariable stable all-pass systems in discrete-time. The first approach involves the tangential Schur algorithm, which employs linear fractional transformations. It stems from the theory of reproducing kernel Hilbert spaces and enables the direct construction of overlapping local parametrizations using Schur parameters and interpolation points. The second approach proceeds in terms of state-space realizations. In the scalar case, a balanced canonical form exists that can also be parametrized by Schur parameters. This canonical form can be constructed recursively, using unitary matrix operations. Here, this procedure is generalized to the multivariable case by establishing the connections with the first approach. It gives rise to balanced realizations and overlapping canonical forms directly in terms of the parameters used in the tangential Schur algorithm

Estimation of salt intake and excretion in children in one region of Switzerland: a cross-sectional study.

PURPOSE Salt intake among children in Switzerland is unknown. The objectives of this study were to determine salt excretion and to identify the main dietary sources of salt intake among children in one region of Switzerland. METHODS We conducted a cross-sectional study using a convenient sample of children 6-16 years of age in Valais, Switzerland, between 2016 and 2018. All children visiting several regional health care providers and without any clinical condition that could affect sodium intake or excretion were eligible. Each child completed a 24-h urine collection to assess salt excretion and two dietary questionnaires to assess dietary sources of salt intake. Weight and height were measured. RESULTS Data were available on 94 children (55 boys and 39 girls; mean age 10.5 years; age range 6-16 years). The mean 24-h salt urinary excretion was 5.9 g [SD 2.8; range 0.8-16.0; 95% confidence interval (CI) 5.3-6.5]. Two-thirds (62%) of the children had salt excretions above recommendations of maximum intake (i.e., ≥ 2 g per day for children up to 6 years of age and ≥ 5 g per day for children 7-16 years of age). The salt excretion tended to be higher during the week-end (6.0 g, 95% CI 5.4-6.6) than during the week (5.4 g, 95% CI 4.3-6.7). The main sources of salt intake were pastas, potatoes, and rice (23% of total salt intake), pastries (16%), bread (16%), and cured meats (10%). One child out of three (34%) added salt to their plate at the table. CONCLUSIONS Salt intake in children in one region of Switzerland was high. Our findings suggest that salt intake in children could be reduced by lowering salt content in commonly eaten foods. TRIAL REGISTRATION NUMBER NCT02900261

Quantitative monitoring of tamoxifen in human plasma extended to 40 metabolites using liquid-chromatography high-resolution mass spectrometry: new investigation capabilities for clinical pharmacology

Liquid-chromatography (LC) high-resolution (HR) mass spectrometry (MS) analysis can record HR full scans, a technique of detection that shows comparable selectivity and sensitivity to ion transitions (SRM) performed with triple-quadrupole (TQ)-MS but that allows de facto determination of "all” ions including drug metabolites. This could be of potential utility in in vivo drug metabolism and pharmacovigilance studies in order to have a more comprehensive insight in drug biotransformation profile differences in patients. This simultaneous quantitative and qualitative (Quan/Qual) approach has been tested with 20 patients chronically treated with tamoxifen (TAM). The absolute quantification of TAM and three metabolites in plasma was realized using HR- and TQ-MS and compared. The same LC-HR-MS analysis allowed the identification and relative quantification of 37 additional TAM metabolites. A number of new metabolites were detected in patients' plasma including metabolites identified as didemethyl-trihydroxy-TAM-glucoside and didemethyl-tetrahydroxy-TAM-glucoside conjugates corresponding to TAM with six and seven biotransformation steps, respectively. Multivariate analysis allowed relevant patterns of metabolites and ratios to be associated with TAM administration and CYP2D6 genotype. Two hydroxylated metabolites, α-OH-TAM and 4′-OH-TAM, were newly identified as putative CYP2D6 substrates. The relative quantification was precise (<20%), and the semiquantitative estimation suggests that metabolite levels are non-negligible. Metabolites could play an important role in drug toxicity, but their impact on drug-related side effects has been partially neglected due to the tremendous effort needed with previous MS technologies. Using present HR-MS, this situation should evolve with the straightforward determination of drug metabolites, enlarging the possibilities in studying inter- and intra-patients drug metabolism variability and related effects. Figure

Scientific Objectives of Einstein Telescope

The advanced interferometer network will herald a new era in observational astronomy. There is a very strong science case to go beyond the advanced detector network and build detectors that operate in a frequency range from 1 Hz-10 kHz, with sensitivity a factor ten better in amplitude. Such detectors will be able to probe a range of topics in nuclear physics, astronomy, cosmology and fundamental physics, providing insights into many unsolved problems in these areas.Comment: 18 pages, 4 figures, Plenary talk given at Amaldi Meeting, July 201

Etude expérimentale de l'écoulement et des charges thermiques dans une tuyère dual bell

Les besoins toujours croissants de l industrie aérospatiale imposent l optimisation de tous les sous systèmes du lanceur. Les tuyères sont actuellement le sous-système présentant les possibilités d optimisation les plus prometteuses. Les tuyères dual bell permettent une adaptation à l altitude par une simple inflexion du contour. L écoulement, est forcé à décoller de façon stable et symétrique à l inflexion, générant ainsi une poussée optimisée à basse altitude. Au cours du vol, lorsque la pression atmosphérique chute sous une certaine valeur, l écoulement attache soudainement dans toute la tuyère, permettant une détente plus importante pour une poussée plus élevée. Ce nouveau concept de tuyères demande à être compris en détail avant son application éventuelle au moteur principal d un lanceur. L étude présentée dans ce document a été réalisée au DLR (centre aérospatial Allemand) de Lampoldshausen dans le cadre d un travail de thèse. Il s agit d une étude fondamentale visant à comprendre le comportement de l écoulement dans une tuyère dual bell, afin de mettre en évidence les paramètres d influence. Une série de tests en gaz froid a été réalisée sur différentes géométries de tuyères. Des mesures de pression et une observation de l écoulement, à l aide d une optique de schlieren a permis de conclure sur l influence de la géométrie sur la transition et sa stabilité face aux variations de pressions et sur le déroulement de la transition d un mode de fonctionnement à l autre. Une série de tests en gaz chaud a permis de réaliser des relevés de températures et pression afin d étudier les charges thermiques dans la paroi au voisinage de l inflexion.The increasing needs of the aerospatial industry impose the optimisation of every subsystems of the launcher. Nozzles are currently the sub-system presenting the most promising possibilities. The dual bell nozzles allow the altitude adaptation of the flow through a simple contour inflection. The inflexion forces the flow to a stable and symmetrical separation, generating an optimised thrust for sea level operation. During the flight, when the ambient pressure decreases under a certain value, the flow suddenly attaches the nozzles wall down to the nozzles end, generating a higher expansion for higher performance. Before its possible application to a launcher main engine, this new nozzle concept must be fully understood. The study presented in this document was made at the DLR (German Aerospace Center) in Lampoldshaussen as part of a PhD. This fundamental study has for pbjective the understanding of the flow behaviour in a dual bell nozzle, in order to define the various parameters of influence. A cold flow test series has been conducted on various nozzle geometries. Pessure measurements have been made and the flow has been observed with schlieren optics in order to determine the influence of the geometry on the transition point, the transition duration and its stability toward pressure variations and the evolution of the flow from one operating mode to the other. Temperature and pressure measurements were also made during a test series under warm gas conditions to investigate the thermal load in the vicinity of the wall inflection.VALENCIENNES-BU Sciences Lettres (596062101) / SudocSudocFranceF

Resolving conflicts in cartographic generalization with problem-resolution methods

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Embedding Generalization in the Framework of a Large Scale Map Database

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