The dark triad is a term used to describe a constellation of three socially harmful personality traits: Machiavellianism, psychopathy, and narcissism. The main aim of the present study was to examine the psychometric properties of the Short Dark Triad (SD3) scale, a brief measure of the dark triad, among a sample (N = 412) of male (n = 200) and female (n = 212) at-risk Portuguese youths. Confirmatory factor analysis revealed the three-factor structure of the SD3 obtained an adequate fit, and measurement invariance across gender was demonstrated, although two items per dimension had to be removed. The Portuguese version of the SD3 scale demonstrated satisfactory psychometric properties, specifically the properties of internal consistency, convergent validity, discriminant validity, and known-groups validity, which overall justifies its use among this population. Findings are discussed in terms of the use of the SD3 scale with male and female at-risk youths.

The production of synthetic natural gas in the context of power-to-gas is a promising technology for the utilization of CO₂. Ni-based catalysts supported on carbon nanotubes (CNTs) were prepared through incipient wetness impregnation and characterized using N₂ adsorption, X-ray diffraction (XRD), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and temperature-programmed reduction (TPR). The catalysts were tested for CO₂ methanation in the 200–400 °C temperature range and at atmospheric pressure. The results demonstrated that the catalytic activity increased with the addition of the CNTs and Ni loading. The selectivity towards CH₄ was close to 100% for the Ni/ZrO₂/CNT catalysts. Reduction of the calcined catalyst at 500 °C using H₂ modified the surface chemistry of the catalyst, leading to an increase in the Ni particles. The CO₂ conversion was dependent on the Ni loading and the temperature reduction in the NiO species. The 10Ni/ZrO₂/CNT catalyst was highly stable in CO₂ methanation at 350 °C for 24 h. Thus, CNTs combined with Ni and ZrO₂ were considered promising for use as catalysts in CO₂ methanation at low temperatures.