Instituto Superior da Maia

In this paper we study the existence and multiplicity of nonnegative solutions for a new class of fractional Schr & ouml;dinger-Kirchhoff systems with a phi-Hilfer fractional operator involving Dirichlet boundary conditions. The approach consists in applying the limit index theory together with the concentration compactness principle for phi-Hilfer fractional derivative spaces and the symmetric criticality principle of Krawcewicz and Marzantowicz. Several interesting mathematical difficulties arise due to the generality of the problem considered.

Emerging adulthood is a period during which individuals shape their lives in increasingly individualized ways. This paper examines how emerging adults experience and interpret adulthood by identifying profiles based on their subjective experiences. The study involved 129 university students (87 female, 39 male, 3 non-binary) from Spain, Portugal, Japan, Korea, Poland, and the USA, who shared reflective essays via an online survey. The sample, drawn from higher-education contexts, offers cross-national perspectives while primarily reflecting the experiences of university-attached youth. Using a constructivist approach, qualitative content analysis was conducted within a mixed-methods framework. Categories of experiences were developed inductively and then deductively, supported by a detailed coding manual and coder training, yielding high intercoder reliability. Hierarchical cluster analysis identified three profiles: (1) Emerging adulthood as uncertainty and struggle; (2) Emerging adulthood as strengthening community and self; and (3) Emerging adulthood as a sense of responsibility and self-awareness. These profiles highlight the complexity and subjectivity of emerging adulthood, emphasizing the need for nuanced perspectives in understanding this developmental stage.

Previous studies have reported a memory advantage for information previously associated with contamination cues (vs. non-contamination)-the contamination effect. In four experiments, we explored the role of emotionality in this effect. Participants recruited on prolific academic saw pictures (Experiment 1, N = 97; Experiment 4, N = 100) or names (Experiment 2, N = 92) of objects alongside illness (vs. neutral) descriptors or objects held by dirty (vs. clean) hands (Experiment 3, N = 100). Then, they recalled the objects and evaluated them in five dimensions. In Experiment 4, participants evaluated the objects before the recall task. The contamination effect was replicated across all experiments. Objects in contamination (vs. non-contamination) conditions were rated as more arousing, negative, disgusting, frightening, and with greater contamination potential. The contamination effect correlated significantly but modestly with the emotional ratings and was fully mediated by contamination potential. These findings suggest that emotionality plays a role but does not fully explain the effect.

Abstract: The digitalization of psychological assessment has introduced new paradigms in the collection, processing, and analysis of data. This paper explores the transformation of psychological testing and assessment in the context of digital footprints and the rise of machine learning (ML) tools. The emergence of smartphones, wearables, and social media platforms has allowed for the collection of passive data, significantly impacting how psychological states are evaluated. This shift offers enhanced insights into personality traits and psychological symptoms, while reducing reliance on traditional self-report methods. However, the use of machine learning to interpret large volumes of behavioral data raises concerns about ethical implications, particularly regarding privacy, consent, and algorithmic transparency. Furthermore, methodological challenges, such as the reliability and validity of AI-based assessments, complicate the integration of these tools into mainstream psychological practice. This paper aims to critically evaluate the benefits and limitations of digital footprints and ML in psychological assessment, emphasizing the need for ethical frameworks and robust methodologies to ensure their effective and safe implementation.

This study examined whether modified badminton game formats enhance player development in U9 and U11 male and female players. Net height was reduced to 135 cm, and court size was adjusted, U9 played on a half double court and U11 on a full court using the double service line, compared with the standard adult format, to assess whether these modifications increase stroke count and improve tactical behavior. Tournaments were conducted using both original and modified formats. Games were analyzed for stroke counts, stroke quality and tactical choices. Stroke data were analyzed using negative binomial generalized linear mixed models (GLMMs), with random effects for game and set. Estimated marginal means (EMMs), incidence rate ratios (IRR), and 95% confidence intervals (CI) were calculated. A total of 35,755 duels across 547 games were analyzed. Modified formats produced significantly fewer strokes per duel (3.45 ± 2.18) than original formats (3.89 ± 2.64; IRR = 0.912, p < 0.001), with differences most pronounced in higher-level players and attenuated in lower-level players. Differences were largest in higher-level players and smaller in lower-level players. Video analysis revealed that modified formats encouraged more short serves (particularly backhand) and increased play at the net, while middle court play remained similar. Gender differences were minimal. In conclusion, modified badminton game formats with lower nets and smaller courts influenced playing behavior in U9 and U11 players particularly in higher-level and older subgroups. Despite the reduced stroke counts, video analysis indicated a shift toward more frontcourts play and short backhand serves, reflecting changes in tactical patterns rather than decreased engagement. These results suggest that scaling game constraints can promote diverse technical and tactical experiences, supporting skill development and enjoyment in youth badminton. These findings suggest that scaling game constraints reshape tactical behavior in youth badminton rather than diminishing engagement. Consequently, governing bodies should align format modifications with skill levels to optimize learning outcomes.