Subsolidus phase equilibria of the CuO – SrO – ZnO pseudoternary system in air at 900 °C

Received: 15.11.2017. Accepted: 01.12.2017. Published: 10.05.2018.The subsolidus phase equilibria of the CuO – SrO – ZnO system were determined at 900 °C in air. The pseudoternary section does not contain ternary oxide phases but is made of 5 three-phase regions and 2 narrow two-phase regions linked to a Sr14Cu24–xZnxO41–y solid solution. The maximum solubility of Zn in this phase is limited to x ≈ 0.1, but this low doping level results in a significant decrease of the electrical resistivity by about one order of magnitude compared to the undoped compound. The other binary oxide phases SrZnO2, Sr2CuO3, and SrCuO2 do not form solid solutions extending into the ternary system. SrZnO2 was found to decompose upon contact with ambient air

On the cohomology algebra of a fiber

Let f:E-->B be a fibration of fiber F. Eilenberg and Moore have proved that there is a natural isomorphism of vector spaces between H^*(F;F_p) and Tor^{C^*(B)}(C^*(E),F_p). Generalizing the rational case proved by Sullivan, Anick [Hopf algebras up to homotopy, J. Amer. Math. Soc. 2 (1989) 417--453] proved that if X is a finite r-connected CW-complex of dimension < rp+1 then the algebra of singular cochains C^*(X;F_p) can be replaced by a commutative differential graded algebra A(X) with the same cohomology. Therefore if we suppose that f:E-->B is an inclusion of finite r-connected CW-complexes of dimension < rp+1, we obtain an isomorphism of vector spaces between the algebra H^*(F;F_p) and Tor^{A(B)}(A(E),F_p) which has also a natural structure of algebra. Extending the rational case proved by Grivel-Thomas-Halperin [PP Grivel, Formes differentielles et suites spectrales, Ann. Inst. Fourier 29 (1979) 17--37] and [S Halperin, Lectures on minimal models, Soc. Math. France 9-10 (1983)] we prove that this isomorphism is in fact an isomorphism of algebras. In particular, $H^*(F;F_p) is a divided powers algebra and p-th powers vanish in the reduced cohomology \mathaccent "707E {H}^*(F;F_p).Comment: Published by Algebraic and Geometric Topology at http://www.maths.warwick.ac.uk/agt/AGTVol1/agt-1-36.abs.htm

Quelles sont les compétences que doit acquérir l'infirmière scolaire pour la gestion du diabète d'un enfant de 4 à 12 ans à l'école ?: une revue de littérature étoffée

L'objectif principal de ce travail est d’identifier les compétences d’une infirmière scolaire face à un enfant diabétique ainsi qu’aux personnes qui l’entourent. De plus, l’objectif second est de trouver des pistes d’action afin d’améliorer la prise en soins de ces enfants et la pratique professionnelle des infirmières scolaires

Information practices in coopetition context: the case of a large video game company

Studies on the information practices in a cooperative context are rare. Yet, issues of access, sharing or retention of information are crucial. This study investigates how professionals in a global digital entertainment company define their information source horizon and the factors that influence them. Using Savolainen’s information horizon methodology, we conducted an exploratory study based on interviews organised at the Montreal studio during which our 29 participants had to place their sources of information on mind maps.Analysis. Quantitative data was collected and analysed on participants' preferences for information sources. We also employed grounded theory techniques to review our interview transcripts using NVivo software. We propose a new categorisation of sources and confirm the typology of Savolainen’s criteria. The results revealed that coopetition and technological contexts shaped information practices of gameworkers. The results of our study on the informational practices of gameworkers could find application in strategic information and knowledge management.Peer Reviewe

Estimation of Autoregressive Fading Channels Based on Two Cross-Coupled H∞ Filters

This paper deals with the on-line estimation of time-varying frequency-flat Rayleigh fading channels based on training sequences and using H∞ filtering. When the fading channel is approximated by an autoregressive (AR) process, the AR model parameters must be estimated. As their direct estimations from the available noisy observations at the receiver may yield biased values, the joint estimation of both the channel and its AR parameters must be addressed. Among the existing solutions to this joint estimation issue, Expectation Maximization (EM) algorithm or crosscoupled filter based approaches can be considered. They usually require Kalman filtering which is optimal in the H2 sense provided that the initial state, the driving process and measurement noise are independent, white and Gaussian. However, in real cases, these assumptions may not be satisfied. In addition, the state-space matrices and the noise variances are not necessarily accurately estimated. To take into account the above problem,we propose to use two crosscoupled H∞ filters. This method makes it possible to provide robust estimation of the fading channel and its AR parameters