OPUS: Open Ulethbridge Scholarship
Open ULeth Scholarship (OPUS) is the University of Lethbridge's open access research repository. It contains a collection of materials related to research and teaching produced by the academic community.
Self-archiving your research in OPUS is one way to meet Open Access policies of granting agencies. It is important to retain your final, post-peer-reviewed drafts for submission to OPUS, as this is often the only version publishers will allow to be archived. Click here for information on the U of L Open Access Policy.
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Sociodemographic factors in older adults’ gait speed decline: a gender disaggregate growth curve analysis of the Ibadan Longitudinal Study of Ageing
(Sage, 2025) Onyeso, Ogochukwu K.; Alumona, Chiedozie J.; Ojagbemi, Akin; Onyeso, Kelechi M.; Odole, Adesola C.; Victor, Janice; Doan, Jon; Bello, Toyin; Gureje, Oye; Awosoga, Olu
Background
Gait speed is an important predictor of older adults’ well-being. We estimated the influence of sociodemographic factors on the gait speed decline of community-dwelling older Nigerians.
Methods
Using the Ibadan Study of Ageing (2007, 2008, and 2009 cycles), we completed a gender disaggregate analysis of sociodemographic influences on participants’ gait speed trajectory using mixed-design ANOVA and growth curve analysis.
Results
At baseline, 53.2% of participants were female, 61.9% were married, with an average age of 75.5 ± 6.8 years and gait speed of 0.96 ± 0.32 m/s. Gender-specific models showed slower gait speed decline in men (β = −0.05, p < .001) compared to women (β = −0.09, p < .001). Widowhood (β = −0.07, p = .001) for women, high socioeconomic status (β = −0.01, p = .009) for men, and chronic disease burden for women (β = −0.02, p = .010) and men (β = −0.03, p = .008) were significant predictors of gait speed decline.
Conclusion
Addressing culture-related widowhood and women’s vulnerabilities, improving health coverage, and promoting lifestyle modifications may mitigate mobility decline among older Nigerians.
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Haar graphical representations of finite groups and an application to poset representations
(Elsevier, 2025) Morris, Joy; Spiga, Pablo
Answering a question of Feng, Kovács, Wang, and Yang, we classify the finite groups admitting a Haar graphical representation. Specifically, we show that every finite group admits a Haar graphical representation, with abelian groups and ten other small groups as the only exceptions.
Our work on Haar graphs allows us to improve a 1980 result of Babai concerning representations of groups on posets, achieving the best possible result in this direction. An improvement to Babai's related result on representations of groups on distributive lattices follows.
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Juvenile male rats form preferences based on strain when playing in groups but not in pairs
(Frontiers Media, 2025) Ham, Jackson R.; Jaiswal, Diya; Waner-Mariquito, Renata; Pellis, Sergio; Achterberg, E. J. Marijke
Like many young mammals, juvenile rats engage in rough-and-tumble play. Play occurs naturally both in wild and laboratory rats, making it a suitable, ethologically relevant behavior to investigate. In the laboratory, rats are typically housed and tested in dyads, despite living in large colonies in the wild. Consequently, when tested in the lab, rats do not have a choice of partners and are instead paired with whomever the researcher selects. Given that both the amount and style of play rats engage in varies considerably depending on the strain of rat being studied, we tested whether rats select play partners based on strain. To do so, juvenile male Long Evans (LE) focal rats (n = 8) were subjected to three play contexts: (1) group play; (2) dyadic play; and (3) social conditioned place preference. During group play, the LE subject rats were given the choice to play with an LE, a Sprague Dawley (SD), or Fischer 344 rat (F344), simultaneously. During dyadic play, focal rats played one-on-one with an LE, SD, or F344 partner. Finally, the rats were conditioned to a context and a social stimulus, with the context either being paired with an LE (preferred stimulus) or F344 (unpreferred stimulus) partner. We found that, when given a choice in a group setting, LE focal rats prefer to play with same-strain partners over both SD and F344 partners. However, when playing under dyadic conditions (i.e., with an assigned partner), LE rats played with each strain equally. Finally, in the socially conditioned place preference test, we found that the focal rats formed preferences for a particular enclosure, but not for the strain. Together, these results suggest that when given a choice, LE rats prefer to play with their own strain, but when they do not have a choice, any strain will do. Given that the testing paradigm can greatly influence the results obtained and the conclusions drawn, our findings highlight the need to consider the research question(s) being asked when determining the most appropriate paradigms to employ.
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Groups of familiar male rats form unstable partner preferences when play fighting during the juvenile period
(Cell Press, 2025) Ham, Jackson R.; Pellis, Sergio
Rats are social animals living in large groups. Within these groups, juveniles engage in vigorous rough-and-tumble play. Despite their natural ecology, most current studies of their play behavior involve pairs not groups. To investigate play under more naturalistic settings, we examined the play of eight groups of juvenile male rats, with each group comprising six, same-aged peers that lived together. Each group was tested on multiple days over the peak play period (30–40 postnatal days). On any given day, rats showed partner preferences for certain individuals in the group, however, preferences varied from day to day. Despite changes in partner preferences, rats chose to play with partners that engaged in more turn taking and with partners with whom they had more symmetrical play relationships. That some individuals within the group were consistently preferred as play partners while others were consistently avoided may have developmental consequences, with those who are favored gaining greater benefits from their juvenile play experiences.
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Over or under: new phylogenetic insights in the evolution of head scratching in birds
(Frontiers Media, 2025) Gutiérrez-Ibáñez, Cristián; Pellis, Vivien; Iwaniuk, Andrew; Pellis, Sergio
Some birds scratch their heads by moving their foot ventrally underneath their wing and others do so by moving their foot over their wing. Two competing hypotheses have been proposed to explain the distribution of these patterns. The phylogenetic hypothesis proposes that the underwing route is a novel pattern evolved in birds as the evolution of wings meant that the foot did not have to move over the front leg as is it does in quadrupeds. Consequently, the overwing route is an atavism reflecting the tetrapod ancestry of birds. The biomechanical hypothesis proposes that body morphology or environmental context determines which pattern is most effective and so explains variation across species. Earlier attempts to test these hypotheses were limited by relatively small, taxonomically biased samples of birds that did not take phylogenetic relationships into account and with few morphological traits explicitly compared. The present study includes data for 1157 species from 92% of avian families and expands the number of morphological traits compared. The most plausible ancestral state, at least for Neoaves, was overwing scratching, turning the original phylogenetic hypothesis on its head. It is also clear from the analyses that head scratching pattern is a highly labile evolutionary trait that, in some orders, repeatedly switches between over and under wing patterns. Moreover, while some morphological traits biased the likely scratching pattern used in some clades, the biomechanical hypothesis failed to predict the pattern of scratching across all birds. The most likely explanation is that the two forms of scratching are independently evolved behavior patterns and that a yet to be determined reason can switch between patterns in different lineages.