Criação de peixes pode ser uma boa alternativa de negócio para o produtor rural brasileiro.

Há mais de 20 anos, a criação de peixes vem se apresentando como uma promissora oportunidade econômica para o empresário rural brasileiro. No início, estimulada pela expansão dos ?pesque-pagues?, a atividade mostrou-se muito lucrativa, permitindo à piscicultura experimentar um crescimento até então inédito no País. Os brasileiros começavam a perceber que os peixes poderiam ser produzidos em cativeiro, sob condições controladas e planejadas, diferentemente da tradicional pesca extrativista. A perspectiva de aumentar o consumo de um alimento nobre passou a fazer parte do dia a dia da população e o setor produtivo percebeu uma excelente alternativa de negócio.bitstream/item/123119/1/Criacao-de-peixes.pd

Quantum Electrodynamics vacuum polarization solver

The self-consistent modeling of vacuum polarization due to virtual electron-positron fluctuations is of relevance for many near term experiments associated with high intensity radiation sources and represents a milestone in describing scenarios of extreme energy density. We present a generalized finite-difference time-domain solver that can incorporate the modifications to Maxwell's equations due to vacuum polarization. Our multidimensional solver reproduced in one dimensional configurations the results for which an analytic treatment is possible, yielding vacuum harmonic generation and birefringence. The solver has also been tested for two-dimensional scenarios where finite laser beam spot sizes must be taken into account. We employ this solver to explore different types of counter-propagating configurations that can be relevant for future planned experiments aiming to detect quantum vacuum dynamics at ultra-high electromagnetic field intensities

Qualidade da água na engorda de tambaqui em viveiros sem renovação da água.

bitstream/CPATC/19780/1/f_18_2007.pd

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

Large scale underground energy storage for renewables integration: general criteria for reservoir identification and viable technologies.

The increasing integration of renewable energies in the electricity grid contributes considerably to achieve the European Union goals on energy and Greenhouse Gases (GHG) emissions reduction. However, it also brings problems to grid management. Large scale energy storage can provide the means for a better integration of the renewable energy sources, for balancing supply and demand, to increase energy security, to enhance a better management of the grid and also to converge towards a low carbon economy. Geological formations have the potential to store large volumes of fluids with minimal impact to environment and society. One of the ways to ensure a large scale energy storage is to use the storage capacity in geological reservoir. In fact, there are several viable technologies for underground energy storage, as well as several types of underground reservoirs that can be considered. The geological energy storage technologies considered in this research were: Underground Gas Storage (UGS), Hydrogen Storage (HS), Compressed Air Energy Storage (CAES), Underground Pumped Hydro Storage (UPHS) and Thermal Energy Storage (TES). For these different types of underground energy storage technologies there are several types of geological reservoirs that can be suitable, namely: depleted hydrocarbon reservoirs, aquifers, salt formations and caverns, engineered rock caverns and abandoned mines. Specific site screening criteria are applicable to each of these reservoir types and technologies, which determines the viability of the reservoir itself, and of the technology for any particular site. This paper presents a review of the criteria applied in the scope of the Portuguese contribution to the EU funded project ESTMAP – Energy Storage Mapping and Planning

Radiographic fetal osteometry: Approach on age estimation for the portuguese population

The estimation of gestational age (GA) on fetal remains can be an important forensic issue. Forensic specialists usually use reference tables and regression equations derived from reference collections, which are quite rare in what fetuses are concerned. Since these tools are mostly grounded on ultrasonographic measurements, which are known to differ from real bones measurements or are based on ancient literature, this study aimed the construction of tables and regression equations for the Portuguese population on the basis of diaphyseal bone length measurements (femur, tibia and humerus) of 100 fetuses of known GA, using post-mortem radiographs. There is a strong correlation between the longitudinal length of studied bones and GA; the femur exhibits the strongest correlation (r = 0.969; p = 0.000), followed by the tibia (r = 0.966; p = 0.000) and the humerus (r = 0.963; p = 0.000). Therefore it was possible to obtain regression equations and to build tables with reference values for each of the diaphysis analyzed