Two of major weeds affecting cereal crops worldwide are Avena fatua L. (wild oat) and Lolium rigidum Gaud. (rigid ryegrass). Thus, development of new herbicides against these weeds is required; in line with this, benzoxazinones, their degradation products, and analogues have been shown to be important allelochemicals and natural herbicides. Despite earlier structure-activity studies demonstrating that hydrophobicity (log P) of aminophenoxazines correlates to phytotoxicity, our findings for a series of benzoxazinone derivatives do not show any relationship between phytotoxicity and log P nor with other two usual molecular descriptors. On the other hand, a quantitative structure-activity relationship (QSAR) analysis based on molecular graphs representing structural shape, atomic sizes, and colors to encode other atomic properties performed very accurately for the prediction of phytotoxicities of these compounds against wild oat and rigid ryegrass. Therefore, these QSAR models can be used to estimate the phytotoxicity of new congeners of benzoxazinone herbicides toward A. fatua L. and L. rigidum Gaud.

No abstract

Herbicides have widely variable toxicity and many of them are persistent soil contaminants. Acetanilide and triazine family of herbicides have widespread use, but increasing interest for the development of new herbicides has been rising to increase their effectiveness and to diminish environmental hazard. The environmental risk of new herbicides can be accessed by estimating their soil sorption (logKoc), which is usually correlated to the octanol/water partition coefficient (logKow). However, earlier findings have shown that this correlation is not valid for some acetanilide and triazine herbicides. Thus, easily accessible quantitative structure-property relationship models are required to predict logKoc of analogues of the these compounds. Octanol/water partition coefficient, molecular weight and volume were calculated and then regressed against logKoc for two series of acetanilide and triazine herbicides using multiple linear regression, resulting in predictive and validated models.

No abstract

The concept of environment in students from primary levels and high school was achieved from an environmental perception analysis based on drawings, while the most important proenvironmental actions, according to the students' opinion, were captured using a survey. The data from environmental perception and the level of pro-environmental actions were correlated to each other using principal component analysis. The hypothesis that meaningful proenvironmental actions are related to the level of environmental perception was confirmed. Thus, teaching-learning activities in environmental education focused on socio-ecological resilience were proposed to improve the environmental perception of students and, ultimately, to lead effective pro-environmental actions. Keywords: environmental perception; pro-environmental actions; educational methodology; socio-ecological system; resilience thinking RESUMO A concepção de ambiente para estudantes da educação básica e ensino médio foi obtida a partir da análise da percepção ambiental baseada em desenhos, enquanto as ações pró-ambientais mais importantes apontadas pelos estudantes foram capturadas por meio de um survey. Os dados de percepção ambiental e o nível das ações pró-ambientais foram correlacionados usando análise por componentes principais. A hipótese de que ações pró-ambientais significativas estão relacionadas com o nível de percepção ambiental foi confirmada. Portanto, atividades de ensino em educação ambiental baseada em resiliência sócio-ecológica são propostas para melhorar a percepção ambiental de estudantes e, consequentemente, conduzir a ações pró-ambientais efetivas.