Hallermann–Streiff syndrome with severe bilateral enophthalmos and radiological evidence of silent brain syndrome: a new congenital silent brain syndrome?

BACKGROUND: We present the first case of a congenital form of silent brain syndrome (SBS) in a young patient affected by Hallermann-Streiff syndrome (HSS) and the surgical management of the associated eyelid anomalies. METHODS: HSS signs were evaluated according to the Francois criteria. Orbital computed tomography (CT) and genetic analysis were performed. An upper eyelid retractor-free recession was performed. Follow-up visits were performed at day 1, weeks 1 and 3, and months 3, 6, 9 (for both eyes), and 12 (for left eye) after surgery. RESULTS: The patient exhibited six of the seven signs of HSS. Orbital CT showed bilateral enophthalmos and upward bowing of the orbital roof with air entrapment under the upper eyelid as previously described for SBS. Genetic analysis showed a 2q polymorphism. During follow-up, the cornea showed absence of epithelial damage and the upper eyelids were lowered symmetrically, with a regular contour. CONCLUSION: Our HSS patient shares features with SBS. We postulate that SBS could include more than one pattern, ie, an acquired form following ventriculoperitoneal shunting and this newly reported congenital form in our HSS patient in whom typical syndromic skull anomalies led to this condition. The surgical treatment has been effective in restoring an appropriate lid level, with good globe apposition and a good cosmetic result

A quasi-Monte Carlo integration method applied to the computation of the Pollaczek integral

Nos remerciements à IEEE pour l'autorisation de mise à disposition du papier complet. © IEEE Copyright Notice : Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.International audienceThis paper presents an effective numeric method to compute Pollaczek integral. This integral is widely used in transmission-line theory when computing the mutual impedance between an overhead conductor and another overhead or underground conductor and the earth-return impedance of an underground cable. At first, we present mutual expressions proposed by Pollaczek and underline the numerical complexities that often lead to the adoption of alternative simplified methods. Then a brief review of the so called "quasi-Monte Carlo" integration method along with its advantages is given. Such an approach is then applied to compute numerically Pollaczek expressions. Comparison between our numerical procedure and an algorithm that has already been published proves both the procedure accuracy, one of its main advantages along with its ease of implementation, and its relatively low time consumption, independent of the input parameters. Finally, as an application example, quasi-Monte Carlo method is used to assess the adequacy, for several study cases, of the simplified formula by Lucca, which is a widely used approximate expression of interest

A Mixed Integer Linear Programming Approach to the Optimal Reconfiguration of Electrical Distribution Networks with Embedded Generators

The paper focuses on the solution of the minimum loss reconfiguration problem of distribution networks, including embedded generation, by means of a mixed integer linear programming (MILP) model. The proposed model takes into account typical operating constraints of distribution networks (radial configuration, branch ampacity limits and bus voltage requirements). The accuracy of the results and the computational performances of the proposed MILP model are evaluated by making reference to test networks already adopted in the literature for the problem of interest

A Synchrophasor Estimation Algorithm for the Monitoring of Active Distribution Networks in Steady State and Transient Conditions

The paper presents a PMU prototype specifically developed for active distribution network applications. The paper describes the method developed to accurately measure the synchrophasors, its implementation into a real-time microcontroller and the relevant characterization in both steady state and transient conditions. Concerning these last points, the paper presents a test procedure suitably conceived to characterize the PMU with both steady state – single tone and distorted – and frequency-varying signals simulating power systems electromechanical transients. The results show that the developed PMU exhibits high accuracy levels that are not modified by the harmonic distortion of the reference signal and by its frequency-varying transient behavior and compatible with their use into power distribution networks

Chapter 14 - Restoration Processes after Blackouts

This chapter aims at illustrating the power system dynamic behavior during restoration scenarios in transmission networks, with particular reference to the analysis of thermal power plant black-start capabilities. This chapter is structured into three parts. Section 14.2 briefly reviews the requirements and the structure of power system restoration processes. The unbundling and liberalization of electrical power systems justifies the reassessment of power system restoration strategies, also by increasing the number of black-start resources, traditionally only represented by hydro stations and gas turbines (GTs). Hence, Section 14.3 deals with the analysis of the black-start capabilities of thermal stations equipped with both steam turbines (STs) and GTs. Moreover, accurate modeling of the dynamic interaction between the power plant and the restoring electrical power system, throughout the use of modern computer simulation tools, appears to be of considerable help to study the early stage of the restoration plans and to design specific control systems to support the feasibility and reliability of black-start maneuvers. Therefore, Section 14.3 also includes the analysis of the typical transients occurring during load restoration maneuvers and islanding formation for two representative types of power plants, namely a once-through boiler steam group repowered by a gas turbine and a combined combined-cycle unit. The models of the two relevant simulators and their identification by means of experimental data are described in Section 14.4