ABSTRACT The present research deals with the two-dimensional knapsack problem by considering the cutting of irregular items from a rectangular plate with defects. While the defects are only known at the time of cutting (in the future), we need first to select which items to produce from cutting the plate. The final items cannot have any defects and the goal is to maximize the profit from cutting the plate and producing the items. We propose a two-stage stochastic optimization model that makes use of a discrete set of scenarios with the realization of the plate defects. The first-stage decisions involve selecting items for cutting and possible production. The second-stage decisions consider the positioning of items in the plate given the scenarios with defects, and then the cancellation and non-production of some selected items, if any. We also extend this model to include a measure of risk, aiming at robust solutions. We perform computational tests on instances adapted from the literature that consider three types of defects, eight scenarios, and four cases for determining each scenario’s probability. The tests evaluate the impact of uncertainties on the problem by calculating the expected value of perfect information and the value of the stochastic solution. The results indicate a percentage reduction in the profit of up to 27.7%, on average, when considering a fully risk-averse decision-maker.

Resumen: Este estudio tuvo como objetivo mapear el perfil de los estudiantes universitarios y la forma en que utilizan las redes sociales. Este es un estudio descriptivo, cuantitativo y transversal realizado en una universidad privada en el sur de Brasil, con la participación de 143 estudiantes. Los resultados mostraron que la práctica de actividades físicas fue reportada por menos de la mitad de los participantes. Pocos informaron haber revisado las redes sociales antes de acostarse. En cuando a las redes sociales, todos los participantes informaron que hacen uso diario de WhatsApp. Con respecto a la adicción a internet, la mayoría tiene una adicción leve a moderada. Se concluyó que las redes sociales, aunque facilitan la comunicación, influyen directamente en la forma en que las personas se relacionan en persona. Se sugiere que estudios futuros mapeen la relación y la influencia de las redes sociales en la vida de los estudiantes universitarios, así como las intervenciones que los ayuden.

Abstract: This study aimed to map the profile of young university students and the way they use social media. This is a descriptive, quantitative and cross-sectional study carried out at a private university in Southern Brazil, with the participation of 143 students. The results showed that the practice of physical activities was reported by less than half of the participants. Few reported checking social media before going to bed. As for social networks and media, all participants reported making daily use of WhatsApp; with respect to Internet addiction, the majority presents mild to moderate addiction. It was possible to conclude that social media, although they are facilitators of communication, directly influence the way people relate to each other in person. It is suggested that future studies map the relationship and influence of social media in university students' lives, as well as interventions that help them.

Resumo: Este estudo teve como objetivo mapear o perfil de jovens universitários e a forma como fazem uso de mídias sociais. Trata-se de um estudo descritivo, quantitativo e transversal, realizado em uma universidade privada do Sul do Brasil, com a participação de 143 alunos. Os resultados apontaram que a prática de atividades físicas foi relata por menos da metade dos participantes. Poucos relataram checar as mídias sociais antes de dormir. Quanto as redes e mídias sociais, todos os participantes relataram fazer uso diário do WhatsApp; no que diz respeito a dependência de internet a maioria apresenta dependência leve a moderada. Foi possível concluir que a as mídias sociais embora sejam facilitadoras da comunicação, influenciam diretamente a forma como as pessoas se relacionam presencialmente. Sugere-se que estudos futuros mapeiem a relação e a influência das mídias sociais na vida de universitários, assim como intervenções que auxiliem os mesmos.

Resumo Muitos estudos têm buscado compreender o que faz as pessoas escolherem e ingerirem determinados tipos de alimentos. Sabe-se que o comportamento alimentar humano é influenciado por uma serie de fatores e, entre estes, os fatores fisiológico e emocional tem ganhado destaque por seu potencial para desencadear dois tipos distintos de estilos alimentares: a alimentação intuitiva e emocional, respectivamente. Com o intuito de promover hábitos saudáveis e minimizar comportamentos alimentares patológicos, a habilidade de Mindfulness tem se mostrado uma ferramenta acessível para auxiliar os indivíduos no contexto das escolhas alimentares. Entretanto, a forma como essas relações acontecem permanece pouco clara no cenário brasileiro, assim como sua observação na população em geral. Desta maneira, a partir de um delineamento quantitativo e explicativo, a presente pesquisa buscou investigar as relações e valores preditivos desta habilidade e de suas dimensões para maiores níveis de alimentação intuitiva e para menores níveis de alimentação emocional. A amostra foi composta de 209 indivíduos com idade superior a 18 anos. Os resultados indicaram que maiores níveis de Mindfulness enquanto escore total e, principalmente, maiores níveis nas dimensões ‘observar’ e ‘não reagir’ predisseram o total da alimentação intuitiva, enquanto que maiores escores de Mindfulness e nas dimensões ‘agir com consciência’ e ‘não reagir’ predisseram menores índices de alimentação emocional. Conclui-se, portanto, que a habilidade de Mindfulness, de fato, contribui para a variação destes estilos alimentares, entretanto, novas pesquisas são necessárias a fim de verificar o impacto de variáveis mediadoras desta relação.

Abstract Many studies have sought to understand what makes people choose and eat certain types of food. It is known that human eating behavior is influenced by a number of factors, and among these, physiological and emotional factors have been highlighted by their potential to trigger two distinct types of eating styles: intuitive and emotional feeding, respectively. In order to promote healthy habits and minimize pathological eating behaviors, Mindfulness's ability has been shown to be an accessible tool to assist individuals in the context of food choices. However, the way these relationships occur remains unclear in the Brazilian scenario, as well as their observation in the general population. Thus, from a quantitative and explicative design, the present research sought to investigate the relationships and predictive values of this ability and its dimensions for higher levels of intuitive feeding and for lower levels of emotional feeding. The sample consisted of 209 participants aged over 18 years. The results indicated that higher levels of Mindfulness as a total score and, mainly, higher levels in the 'observe' and 'not react' dimensions predicted the total of the intuitive feeding, while higher Mindfulness scores and in the dimensions 'acting with conscience' not react’ predicted lower rates of emotional eating. It is concluded, therefore, that the ability of Mindfulness, in fact, contributes to the variation of these food styles, however, new research is necessary in order to verify the impact of mediating variables of this relation.

ABSTRACT Solving nesting problems or irregular strip packing problems is to position polygons on a fixed width and unlimited length strip, obeying polygon integrity containment constraints and nonoverlapping constraints, in order to minimize the used length of the strip. To ensure non-overlapping, we use separation lines, i.e., straight lines that separate polygons. We present a nonlinear programming model that considers free rotations of the polygons and of the separation lines. This model uses a considerable smaller number of variables than the few other approaches proposed in the literature. We use the nonlinear programming solver IPOPT (an algorithm of interior points type), which is part of COIN-OR. Computational tests were run using established benchmark instances and the results were compared with the ones obtained with other methodologies in the literature that use free rotations.