Stefano Ricci

Genetic and neuroradiological heterogeneity of double cortex syndrome

Mutations in the X‐linked doublecortin gene appear in many sporadic cases of double cortex (DC; also known as subcortical band heterotopia), a neuronal migration disorder causing epilepsy and mental retardation. The purpose of this study was to examine why a significant percentage of sporadic DC patients had been found not to harbor doublecortin mutations and to determine whether clinical features or magnetic resonance imaging scan appearance could distinguish between patients with and without doublecortin mutations. Magnetic resonance imaging scan analysis differentiated patients into the following four groups: anterior biased/global DC with doublecortin mutation (16 of 30; 53%), anterior biased/global DC without mutation (8 of 30; 27%), posterior biased DC without mutation (3 of 30; 10%), and limited/unilateral DC without mutation (3 of 30; 10%). The presence of these atypical phenotypes suggests that other genetic loci or mosaicism at the doublecortin locus may be responsible for this diversity of DC cases. Ann Neurol 2000;47:265–269

Photic stimulation - Standardization of screening methods.

PURPOSEnDifferences in methodology of intermittent photic stimulation within and between countries in Europe make collaborative research and interpretation of results difficult.nnnMETHODnExperts in the field of photic stimulation from European countries have given an overview of methods used in routine photic stimulation. A consensus meeting was organized in May 1996 in the Netherlands.nnnRESULTSnMethodology, including specification of a photo stimulator, procedure of photic stimulation, and interpretation of EEG results, has been defined according to available scientific and clinical knowledge.nnnCONCLUSIONSnConsensus was reached in setting up a safe, quick, simple and reliable method to determine whether or not patients are photosensitive. A specification of an international standard for intermittent photic stimulation in the routine EEG examination is given with the purpose of improving patient care and facilitating collaborative research.

Video-game epilepsy: a European study.

With the introduction of Nintendo video‐games on a large scale, reports of children having seizures while playing suggested a possible specific, provocative factor. Although 50% of the photosensitive patients are also sensitive to a 50‐Hz television, nonphotosensitive patients with a history of videogame seizures were described as well. The question arises whether this is a mere coincidence, provoked by fatigue and stress, is related to the reaction to the television screen itself, or depends on the movement and color of the pictures of this specific game.

Epilepsy provoked by television and video games, Safety of 100-Hz screens

Television (TV) and video games (VG) can provoke seizures in patients with photosensitive epilepsies. Flicker frequency is the most important factor in screen activation. We tested conventional 50-Hz versus 100-Hz monitors during TV viewing and VG playing in 30 photosensitive subjects, 23 of whom had a history of TV or VG seizures or both. Fifteen subjects discharges were activated by 50-Hz TV; 17 by 50-Hz VG; and one by a 100-Hz screen. Thus, 100-Hz screens protect against screen activation.

The caliber of the human long saphenous vein and its congenital variations

The purpose of the present study is to evaluate the caliber of the normal human long saphenous vein (LSV) in order to verify the occurrence of congenital narrowings. The LSV morphology was evaluated by the dissection of 32 cadaveric limbs, and by ultrasonography of 102 healthy living subjects. The LSV caliber was constant in most of the limbs, showing only a mild and progressive increase from the ankle to the groin. Furthermore, great individual variation in LSV caliber was found. A segmental narrowing of the LSV was present in 39.8% of limbs. The narrow segment was visible with the naked eye during dissection or by ultrasonography in 22.4% of cases (LSV hypoplasia). In the remaining 17.4% the caliber was so reduced that it could only be detected microscopically (LSV aplasia). In relation to the narrow segments, the main ascending flow was shunted in a collateral vein running within the superficial hypodermis. The narrow segments of the LSV had a weaker and less muscular wall than did those of normal caliber. Hypoplasia and aplasia of the LSV are probably due to segmental failure in the development of the vessel, and represent a risk factor for varicosis. In fact, the ascending flow is shunted from the LSV in a collateral vein that runs in the yielding superficial fatty layer of the hypodermis. Furthermore, the high incidence of LSV segmental hypoplasia and aplasia has also to be considered whenever this vein is used as an arterial graft, because of the marked anatomical remodelling.

Railway traffic on high density urban corridors: Capacity, signalling and timetable

In the paper a study on the correlation among capacity, block sections length, typology of services and timetables for high density lines such as urban railway corridors is presented. The adopted methodology is explained as well as the use of simulation for the analysis of sensitivity. Stability and robustness of selected timetables are investigated. In particular, railway system’s performances are linked to timetable planning criteria, i.e. to the definition of appropriated recovery times and buffer times, which influence the definition of available capacity. The possibility to find a trade-off value among these parameters is described. In this context the differences between theoretical timetables (which are defined by technical features of infrastructure and rolling stock) and the adopted timetables (which include recovery and buffer times and are functional to a defined level of service) are explained. The estimation of correlations among capacity, block sections length, timetable and operational plan is conceived as a basis to provide guidelines to design new urban railways or to evaluate possible reliability effects of actions on block sections (often with changes on the adopted signalling) or timetables.

The Effect of Video‐Game Software in Video‐Game Epilepsy

Purpose: The individual role of video‐game (VG) programs in VG activation is still unclear. Strict relations between VG seizures and photo‐ and pattern sensitivity suggest that programs per se may have a role in seizure activation.

Simulation of stochastic elements in railway systems using self-learning processes

Abstract The railway traffic follows deterministic rules, whose selection and application depend on the choices of human operators. These choices may be different in similar situations and produce different effects on the circulation. The difficulty to code, in a general and comprehensive way, these behaviours suggested to test the use of systems capable to reproduce events without requiring a previous definition of the operating rules but acting by means of self-learning processes. The present research deals with: • an analysis of the critical behavioural parameters, difficult to be effectively modelled by means of analytical simulation tools; • the selection of the self-learning process for the application to the reliability of a railway network capable to work as a part of a wider simulation model of railway traffic; • the development of a preliminary version of the model simulating the stochastic failure events and its application to a case study.

A synthetic approach to the evaluation of the carrying capacity of complex railway nodes

The evaluation of carrying capacity of complex railway nodes is a typical problem to be faced in metropolitan areas. This paper initially analyzes a few methods (Potthoff methodology, Probabilistic approach and Deutsche Bahn procedure) for the evaluation of carrying capacity of complex railway nodes. The aim of the article is to investigate commonalities and differences among these methods in order to try (even in the continuation of the research) to identify potential margins of improvement or to formulate a new approach to evaluate the use of stations in a synthetic mode, considering the characteristics and the limits of the existing and analyzed models. The results of the theoretical analysis have been validated by means of applications to typical case studies.

A supply-demand study of practice in rail logistics higher education

This paper includes a study conducted to analyse the current state of supply and demand for higher education in rail logistics. More specifically the study presented consists of two surveys, as follows. The first survey, Supply Survey, explores existing transport and logistics-related courses and educational programmes offered in higher education institutions. The second survey, Demand Survey, examines demands for rail logistics higher education and aims to understand the current needs for higher education in the sector. This paper shows that a spectrum of rail, freight transport and logistics related courses and programmes exist, however there is a strong need for a more specific training and education offering operations management skills needed to improve the company performance, efficiency and quality of service provided.