2,464 research outputs found
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
Voltammetric study and electrochemical degradation of reactive dyes
The aim of this study was, in a first stage, to investigate the voltammetric behavior of two reactive dyes, C.I.Reactive Orange 16 and C.I.Reactive Blue 19. Cyclic voltammetry technique (CV), on a glassy carbon electrode, was used for this purpose in order to identify the electrochemical activity of the chromophore group in each case, in the present experimental conditions. A second part of the study was to investigate the electrochemical degradation of the dyes, in the presence of hydrogen peroxide and copper ions. The reaction between the two species leads to the generation of hydroxyl radicals, which causes the oxidation and degradation of the organic compounds. The efficiency of dye degradation and ecolorization were evaluated by color removal and COD values. Depending on electrolysis time, applied potential, hydrogen peroxide concentration and dye concentration, different stages of color removal were attained
PHM overview on battery models approaches
The Battery Management Systems (BMS) brought a new impetus to the battery energy
management which lead to an increase in battery life. But the BMS fails when the State
of Charge (SoC), State of Health (SoH), State of Life (SoL) or Remaining Useful Life
(RUL) prognostics systems do not provide the required accuracy. Despite the increase of
complexity and accuracy of battery models, the poor performance with floating
temperature and load profiles persists. With the development of innovative products on
wide-ranging applications, the battery materials, technologies, reliability and safety are
being pressed to their limits. Therefore, a huge amount of work is still necessary, not only
on the development of new battery technologies but also on the BMS, battery models and
metrics accuracy improvements. The paper gives a comprehensive overview of the
applicability, accuracy, weaknesses and advantages of the most recent battery models.
The paper will also discuss how the Prognostics Health Management (PHM) can support
a technologic impetus on battery affairs with battery models and metrics accuracy
improvements.info:eu-repo/semantics/publishedVersio
Lepton flavor violation in SUSY left-right symmetric theories
The seesaw mechanism is the most popular explanation for the smallness of
neutrino masses. However, its high scale makes direct tests impossible and only
indirect signals at low energies are reachable for collider experiments. One of
these indirect links with the high scale is lepton flavor violation (LFV). We
discuss LFV decays of sleptons in the context of a SUSY left-right symmetric
model that naturally incorporates the seesaw mechanism. This non-minimal
embedding of the seesaw leads to observable LFV effects in the right-handed
sleptons sector, contrary to minimal models where these are found to be totally
negligible. Therefore, LFV observables can be used as a powerful tool to study
physics right below the GUT scale.Comment: To appear in the proceedings of PASCOS 2010, the 16th International
Symposium on Particles, Strings and Cosmology, Valencia, Spai
No Place for Pointless Jobs: How Social Responsibility Impacts Job Performance
We address the question of how organizations’ practices of social responsibility impact their
employees’ job performance. Independent studies have shown that job performance is influenced
by how employees perceive the organization they work for and how they perceive the work they
perform for the organization. Moreover, studies on the relationship between social responsibility
and job performance have shown that employees’ perceptions of their organization mediate the
relationship. What is thus far neglected, however, is whether and how their perceptions of work
itself mediate the relationship as well. We derive a sequential mediation model according to which
social responsibility improves job performance by contributing to a supportive and trustworthy
work context (employees’ perceptions of the organization they work for), in turn promoting work
meaningfulness and engagement (employees’ perceptions of work itself). We collect survey data and
test the sequential mediation model against a series of alternative models, each of which challenges
a specific assumption of the proposed model. Our model provides the best tradeoff between the
accuracy and the parsimony with which it describes the data collected, and is, therefore, expected to
generalize best to other data.info:eu-repo/semantics/publishedVersio
Prebiotic xylo-oligosaccharides as high-value co-products on an integrated biorefinery approach from lignocellulosic feedstock
The present work proposes the production of prebiotic xylo-oligosaccharides (XOS) as high-value co-products of the Lignocellulose Feedstock Biorefinery concept, foreseeing potential applications on food, feed and nutraceutical industries. Autohydrolysis was used to selectively solubilise the hemicellulosic fraction of several xylan-rich, widely available, agricultural, agro-industrial and forestry by-products: corn cobs, brewery’s spent grain and Eucalyptus wood chips. The soluble hemicellulose-rich and the solid cellulose- and lignin-rich fractions were separated, and the crude XOS-rich hydrolysates were further purified by gel filtration chromatography. Selected fractions of purified XOS within the desired ranges of polymerization degree were characterised and their prebiotic potential was investigated in in vitro fermentations by bifidobacteria, lactobacilli and intestinal inocula. Parameters such as bacterial growth and XOS consumption were evaluated and compared with commercially available xylo-oligosaccharides. The differences observed were considered of relevance for the formulation of symbiotic preparations and the future design of targeted, tailor-made prebiotic xylo-oligosaccharides
sanidade avĂcola contribui para o crescimento da produção de aves.
Projeto: 11.11.11.111
New amino acid-based thiosemicarbazones and hydrazones: synthesis and evaluation as fluorimetric chemosensors in aqueous mixtures
A series of new phenylalanine derivatives bearing thiosemicarbazone and hydrazone units at the side chain were synthesised and evaluated as fluorimetric chemosensors for ions. They were tested for the recognition of organic and inorganic anions, (such as AcO-, F-, Cl-, Br-, I-, ClO4-, CN-, NO3-, BzO-, OH-, H2PO4- and HSO4-) and of alkaline, alkaline-earth, and transition metal cations, (such as Na+, K+, Cs+, Ag+, Cu+, Cu2+, Ca2+, Cd2+, Co2+, Pb2+, Pd2+, Ni2+, Hg2+, Zn2+, Fe2+, Fe3+ and Cr3+) in acetonitrile and its aqueous mixtures in varying ratio through spectrofluorimetric titrations. The results indicate that there is a strong interaction through the donor N, O and S atoms at the side chain of the various phenylalanines, with higher sensitivity for Cu2+, Fe3+ and F- in a 1:2 ligand-ion stoichiometry. The photophysical and metal ion sensing properties of these phenylalanines suggest that they can be suitable for incorporation into peptidic chemosensory frameworks.This research was funded by the Foundation for Science and Technology (FCT) for financial support to CQ-UM [PEst-C/QUI/UI0686/2013 (FCOMP-01-0124-FEDER-037302)], CQUM
(UIDB/00686/2020) and a PhD grant to C.I.C. Esteves (SFRH/BD/68360/2010). The NMR spectrometer Bruker Avance III 400 is part of the National NMR Network and was purchased within the
framework of the National Program for Scientific Re-equipment with funds from POCI 2010 (FEDER)
and FC
Amino acids based on 2,4,5-triarylimidazoles: synthesis and evaluation as new chemosensors for ion recognition
Sciforum Electronic Conference Series, Vol. 17, 2013, b015N-tert-butyloxycarbonyl-4-formylphenylalanine methyl ester and appropriate heterocyclic diones were used in the synthesis of novel fluorescent unnatural amino acids, namely 2,4,5-triarylimidazolyl-alanines. These new compounds were fully characterised by the usual spectroscopic techniques, such as IR and NMR. The photophysical properties of the amino acids were evaluated by UV-Vis absorption and fluorescence spectroscopy in solvents of different character. Interaction studies with biologically and analytically important ions such as F-, OH-, Cu2+ and Fe3+, through spectrophotometric and spectrofluorimetric titrations were carried out to assess their potential as chemosensors.Fundação para a Ciência e a Tecnologia (FCT
- …