Browsing by Author "Pereira, Joana"
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- Coping as a moderator of the influence of economic stressors on psychological healthPublication . Neves de Jesus, Saul; Leal, Ana Rita; Viseu, J.; Matavelli, Rafaela Dias; Pereira, Joana; Greenglass, Esther; Pinto, PatríciaSince 2008, there has been a decline in the economy of several European countries, including Portugal. In the literature, it is emphasized that periods of economic uncertainty propitiate the appearance of mental health problems and diminish populations? well-being. The aim of the present study, with 729 Portuguese participants, 33.9% (n=247) males and 66.1% (n=482) females with an average age of 37 years old (M=36.99; SD=12.81), was to examine the relationship between economic hardship, financial threat, and financial well-being (i.e., economic stressors) and stress, anxiety, and depression (i.e., psychological health indicators), as well as to test the moderation effect of coping in the aforementioned relationship. To achieve these goals, a cross-sectional design was implemented and structural equation modeling (SEM) was used to analyze the obtained data. Our results underline that coping affects the relationship between economic stressors and psychological health since subjects with lower coping levels are more vulnerable to economic stress factors than those with higher coping levels. The moderation effect was more evident in the relationships between economic hardship and stress, anxiety, and depression. The main implications of this study are presented, as well as its? limitations and suggestions for future research.
- Interacção do vanádio com a miosina de músculo esquelético de coelhoPublication . Pereira, JoanaA exposição a vanádio conduz a uma diminuição na actividade ATPásica da miosina e provoca a oxidação dos grupos sulfidrilo desta proteína. No entanto, não está integralmente esclarecido quais os efeitos específicos que ocorrem na miosina quando exposta ao vanádio. Nesse sentido, interessou determinar in vitro quais as alterações estruturais, funcionais e moleculares ocorridas no Subfragmento-1 de miosina de músculo esquelético de coelho após a exposição crónica a soluções de metavanadato, decavanadato e vanadilo. Verificou-se que a exposição de S1 (0,05 mg/mL) a decavanadato inibe a sua actividade Mg2+-ATPásica, sendo o valor de IC50 para esta inibição de 26,6 ± 0,7 µM decavanadato. Na presença de actina, o valor de IC50 é de 28 ± 1 µM decavanadato. A perda de funcionalidade proteica poderá dever-se à oxidação de 2 resíduos de Cys de S1 não expostos ao solvente, após exposição a 1000 µM de decavanadato. Verificou-se que as espécies oligoméricas de vanádio com maior afinidade para o S1 são o decavanadato e o tetravanadato. Revelaram-se os possíveis ligandos do vanádio no S1, através de espectroscopia de RPE. Globalmente, os resultados obtidos sugerem um efeito significativo do vanádio, nos estados de oxidação (IV) e (V) na estrutura e função do S1, em concentrações facilmente alcançáveis daquele metal no ambiente terrestre. The exposure to vanadium leads to a decrease of the myosin ATPase activity and provokes the oxidation of its sulfydryl groups. However, the specific effects of vanadium on myosin are not yet fully understood. Consequently, the objectives of the present work were to establish the structural, funtional and molecular changes suffered by rabbit myosin subfragment-1 after cronic exposure to metavanadate, decavanadate and vanadyl solutions. It was verified that the exposure of S1 (0,05 mg/mL) to decavanadate results in the inhibition of its Mg2+-ATPase activity, resulting in the IC50 value 26,6 ± 0,7 µM decavanadate. In the presence of actin, the IC50 value was 28 ± 1 µM decavanadate. It is suggested that the loss of protein function may be due to the oxidation of 2 core cysteine residues, after exposure to 1000 µM decavanadate. It was also observed that the decavanadate and tetravanadate species show the highest affinity for S1. Lastly, the possible S1 ligands to vanadium were revealed, through EPR spectroscopy. Globally, the obtained results point to significant effect of V(V) and V(IV) states on S1 structure and function, for easily reachable environmental vanadium concentrations.
- Relationship BetweenTeacher Motivation and Organizational Variables: ALiterature ReviewPublication . Viseu, J.; Jesus, Saúl; Rus, Claudia; Canavarro, Jos? Manuel; Pereira, JoanaAbstract Teacher motivation plays a central role in education because ofitsimpacton student motivation. Previous reviews of teacher motivation have focused on individual variables and psychopathology indicators. However, it is also important to understand the effect of organizational variableson teacher motivationbecause these highlightthe contextthat the teacher is a part of(i.e.,the school). The literature review in this paper analysed studies related to teacher motivation and a pre-defined group of organizational variablesthat werepublished between 1990 and 2014 in several electronic databases.The study found that organizational culture was the most studied variable associated with teacher motivationand most studies in this area were published between 2010 and 2014.Further,there was a prevalence of quantitative studies. This paper concludes with the theoreticaland practical implications of the results,as well assuggestions for future research directions.