Are the effects of unreal violent videogames pronounced when playing with a virtual reality system?

This study was conducted to analyze the short-term effects of violent electronic games, played with or without a virtual reality (VR) device, on the instigation of aggressive behavior. Physiological arousal (heart rate (HR)), priming of aggressive thoughts, and state hostility were also measured to test their possible mediation on the relationship between playing the violent game (VG) and aggression. The participants—148 undergraduate students—were randomly assigned to four treatment conditions: two groups played a violent computer game (Unreal Tournament), and the other two a non-violent game (Motocross Madness), half with a VR device and the remaining participants on the computer screen. In order to assess the game effects the following instruments were used: a BIOPAC System MP100 to measure HR, an Emotional Stroop task to analyze the priming of aggressive and fear thoughts, a self-report State Hostility Scale to measure hostility, and a competitive reaction-time task to assess aggressive behavior. The main results indicated that the violent computer game had effects on state hostility and aggression. Although no significant mediation effect could be detected, regression analyses showed an indirect effect of state hostility between playing a VG and aggressio

A concern visualization approach for improving MATLAB and octave program comprehension

The literature has pointed out the need for focusing efforts to better support comprehension of MATLAB and Octave programs. Despite being largely used in the industry and academia in the engineering domain, programs and routines written in those languages still require efforts to propose approaches and tools for its understanding. Considering the use of crosscutting concerns (CCCs) to support the comprehension of object-oriented programs, there is room of its use in the context of MATLAB and Octave programs. The literature has purpose and examples in this direction. Considering this scenario, we propose the use of visualization enriched with CCCs representation to support the comprehension of such programs. This paper discusses the use of a multiple view interactive environment called OctMiner in the context of two case studies to characterize how collected information relating to crosscutting concerns can foster the comprehension of MATLAB and GNU/Octave programs. As a result of the conducted case studies, we propose strategies based on OctMiner and tailored to support different comprehension activities of programs written in MATLAB and Octave.info:eu-repo/semantics/acceptedVersio

BitTorrent based transmission of real-time scalable video over P2P networks

The number of software applications available on the Internet for distributing video streams in real time over P2P networks has grown quickly in the last two years. Typical this kind of distribution is made by television channel broadcasters which try to make their content globally available, using viewer's resources to support a large scale distribution of video without incurring in incremental costs. However, the lack of adaptation in video quality, combined with the lack of a standard protocol for this kind of multimedia distribution has driven content providers to basically ignore it as a solution for video delivery over the Internet. While the scalable extension of the H.264 encoding (H.264/SVC) can be used to support terminal and network heterogeneity, it is not clear how it can be integrated in a P2P overlay to form a large scale and real time distribution. In this paper, we start by defining a solution that combines the most popular P2P file-sharing protocol, the Bit Torrent, with the H.264/SVC encoding for a real-time video content delivery. Using this solution we then evaluate the effect of several parameters in the quality received by peers

The magnitude of the variation in glycemia: a new parameter for risk assessment in acute coronary syndrome?

INTRODUCTION AND OBJECTIVES: The aim was to evaluate the relationship between the magnitude of the variation in the level of glycemia during hospitalization and in-hospital and long-term mortality and postdischarge endpoints in two groups of patients with acute coronary syndrome: those with and those without a previous diagnosis of diabetes. METHODS: The study included 1210 patients admitted for acute coronary syndrome between May 2004 and July 2007. The study population was divided in two subgroups: patients with a previous diagnosis of diabetes (n=386) and nondiabetics (n=824). Each subgroup was further divided into four smaller groups according to the quartile of glycemia variation: diabetics (Q1: or=164 mg/dl) and nondiabetics (Q1: or=60 mg/dl). Patients were followed up for an average of 18 months after the occurrence of the acute coronary syndrome. RESULTS: In diabetic patients, there was no relationship between the magnitude of the glycemia variation and in-hospital or postdischarge endpoints. In nondiabetics, no significant difference was observed in in-hospital mortality or morbidity, but statistically significant clinical differences were found during follow-up. Multivariate regression analysis showed that Q4 versus Q1, age >or=70 years, and previous antiplatelet or angiotensin-converting enzyme inhibitor therapy were independent predictors of postdischarge endpoints in the nondiabetic group. CONCLUSIONS: In nondiabetic acute coronary syndrome patients, the magnitude of the variation in glycemia observed during hospitalization was a strong independent predictor of postdischarge clinical endpoints

Dynamical instability in kicked Bose-Einstein condensates: Bogoliubov resonances

Bose-Einstein condensates subject to short pulses (`kicks') from standing waves of light represent a nonlinear analogue of the well-known chaos paradigm, the quantum kicked rotor. Previous studies of the onset of dynamical instability (ie exponential proliferation of non-condensate particles) suggested that the transition to instability might be associated with a transition to chaos. Here we conclude instead that instability is due to resonant driving of Bogoliubov modes. We investigate the excitation of Bogoliubov modes for both the quantum kicked rotor (QKR) and a variant, the double kicked rotor (QKR-2). We present an analytical model, valid in the limit of weak impulses which correctly gives the scaling properties of the resonances and yields good agreement with mean-field numerics.Comment: 8 page