On minimal extensions of rings

Given two rings $R \subseteq S$, $S$ is said to be a minimal ring extension of $R$ if $R$ is a maximal subring of $S$. In this article, we study minimal extensions of an arbitrary ring $R$, with particular focus on those possessing nonzero ideals that intersect $R$ trivially. We will also classify the minimal ring extensions of prime rings, generalizing results of Dobbs, Dobbs & Shapiro, and Ferrand & Olivier on commutative minimal extensions.Comment: 25 page

The role of Big Data in explaining disaster resilience in supply chains for sustainability

The purpose of this paper is to propose and test a theoretical framework to explain resilience in supply chain networks for sustainability using unstructured Big Data, based upon 36,422 items gathered in the form of tweets, news, Facebook, WordPress, Instagram, Google+, and YouTube, and structured data, via responses from 205 managers involved in disaster relief activities in the aftermath of Nepal earthquake in 2015. The paper uses Big Data analysis, followed by a survey which was analyzed using content analysis and confirmatory factor analysis (CFA). The results of the analysis suggest that swift trust, information sharing and public-private partnership are critical enablers of resilience in supply chain networks. The current study used crosssectional data. However the hypotheses of the study can be tested using longitudinal data to attempt to establish causality. The article advances the literature on resilience in disaster supply chain networks for sustainability in that (i) it suggests the use of Big Data analysis to propose and test particular frameworks in the context of resilient supply chains that enable sustainability; (ii) it argues that swift trust, public private partnerships, and quality information sharing link to resilience in supply chain networks; and (iii) it uses the context of Nepal, at the moment of the disaster relief activities to provide contemporaneous perceptions of the phenomenon as it takes place. Vol 142 (2) pp.1108-111

Étude du comportement mécanique d'une pale de turbine kaplan en régime transitoire

A very comprehensive series of tests has been run on a big Kaplan turbine at the Beauchastel power plant on the Rhone with the following main objects in view : __ (i) To try out special techniques, for example sticking strain gauges in high velocity flows, fitting multi-conductor wires inside the turbine hub, among the blade control links and through the governor tube, designing a slip ring for low background noise or a radio transmission system between the turbine runner and power house, etc.; (ii) Direct turbine runner blade load and stress measurement ; (iii) Comparison of stresses measured under various normal and abnormal operating conditions. Normal (i.e. everyday) operation is considered to include no-load running, stopping, emergency shut-down, and routine running, whilst cases of abnormal operation either seldom occur (runaway) or are of a new kind (relief or sluice operation). With the results of these tests, blade behaviour can be investigated as follows : __ a) By measurement of local stresses due to hydrodynamic forces acting on the blade; b) By calculation of the total hydrodynamic load components from measured local dynamic data and static calibration results. This also enables a link to be established between these results and the model data, and the model tests to be used for types of operation liable to be dangerous on the prototype. Special instrumentation used comprised thirteen strain gauge bridges connected to five-channel frequency modulation transmitting equipment and an eight-channel slip ring providingdata straight from the blade. AlI this information was recorded for both steady and transient conditions. As a general rule, the measured hydrodynamic stresses were low. At partial runaway condition with twice the normal running speed and half the rated discharge, the highest bending stress was 8.5 kg/sq.mm at a point on the blade centre-line a quarter of a runner radius in from the blade tip. These values would certainly be very much higher at the absolute maximum runaway condition. All the extreme values recorded were associated with major variations in the hydrodynamic operating conditions, e.g. with the guide vanes near the end of their closing travel, the flow cut off by the gate, maximum speed, etc. Compression and tensile stresses recorded under transient conditions at the blade leading edge near the root of the blade were low and invariably less than those observed for steady operation. Normal stress fluctuations were up to ± 25 % at low frequency (1 to 2 cycles/second). Alternating stresses were apt to occur with comparatively high frequencies (30 to 60 cycles/second), being of a low level (± 0.3 kg/sq.mm). They were recorded by all the gauges simultaneously when the turbine cut out at low speed (0.75 n0) and acted as a pump in the draught tube with the downstream in the process of closing. The components of the total hydrodynamic load acting on the blade and the coordinates of its P.O.A. were calculated from these results for both steady and transient conditions. A check on the values found in this way showed them to be representative to within 10 % of the actual blade stress values. The inference from these calculations is that the total hydrodynamic load component normal to the blade depends on the same relationships as bending stress, confirming that the latter play a decisive part compared to torsional stresses

The problem of emergency supply: Best practice in the preparation and response phases

This paper discuss the problems inherent in planning and responding to disaster events in a multi-agency context where numerous actors and agencies are involved in the planning and response phases. In particular we examine a situation where a lead agency has been delegated the responsibility for emergency supply and how it determines best practice. Exploratory in-depth interviews were conducted with 12 CDEM organisations and key managers within Australasia who highlighted a number of emergency supply issues. We discuss the problem of coordinated supply management in developed countries where mandated/lead response agencies are required to meet stakeholder and local community expectations and outcomes. From this we then formulate a scenario based model for disaster planning that incorporates; desired outcomes, scale, resources, constraints and agency integration to better manage the desired response. Finally, we offer a range of practical recommendations to assist multi-agent coordinated of supply management. Humanitarian logistics is usually examined from a developing country perspective, yet efficient and effective disaster response is no less important for modern economies. In this respect we offer a relatively novel scenario based planning model that incorporates community outcomes from the beginning and should facilitate interagency cooperation to achieve best practice for emergency logistics

Le Politicomane et le nihiliste, ou le Pour et le contre, par J. Lagarde et J. L'Hermitte

Avec mode text

Vibrational dynamics in molecular condensed phases with the CLIO free electron laser

International audienc

Hemispherectomy - a Further Modification Using Omentum Vascularized Free Flaps

This report describes the authors' technique designed to further prevent the late complications of hemispherectomy. A vascularized omental free flap is used to fill the extradural dead space left following the procedure advocated by Adams. This procedure may provide further stability to the residual brain and reduce infective complications