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Friendship is a unique and underexplored area of human sociality. Research suggests that humans have preferences for characteristics in their friends that maximize the benefits of these relationships. Yet, whereas more friends might increase friendship benefits, humans also have limited time, resources, and energy to invest in finding high-quality friends, making it likely that the nature of these preferences differs depending on the resources an individual has available to invest in this goal. Across two studies (total N = 693), we investigated how this trade-off may function by investigating the nature of friendship preferences. In Study 1, we utilized the budget paradigm method from behavioral economics to investigate the necessities and luxuries in friendship preferences. In Study 2, we replicated these preferences with a novel method and extended our investigation into understanding the hierarchical nature of these preferences. Taken together, our results provide a promising starting point for research investigating trade-offs between necessities and luxuries in friendship preferences.

Did the COVID-19 pandemic bring people together or push them apart? While infectious diseases tend to push people apart, crises can also bring people together through positive interdependence. We studied this question by asking an international sample (N = 1,006) about their inclinations to cooperate, perceptions of interdependence (i.e., shared fate), and perceived risk as well as local prevalence of COVID-19 infection across 14 time points from March to August, 2020. While perceived interdependence with others tended to increase during this time period, inclinations to cooperate decreased over time. At the within-person level, higher local prevalence of COVID-19 attenuated increases in perceived interdependence with others, and was associated with lower inclinations to cooperate. At the between-person level, people with high perceived interdependence with others reported more stable, or increasing, inclinations to cooperate over time than people with low perceived interdependence. Establishing a high sense of perceived interdependence with others may thus allow people to maintain cooperation during crises, even in the face of challenging circumstances such as those posed by a highly transmissible virus. [ABSTRACT FROM AUTHOR]

Friendship is a unique and underexplored area of human sociality. Research suggests that humans have preferences for characteristics in their friends that maximize the benefits of these relationships. Yet, whereas more friends might increase friendship benefits, humans also have limited time, resources, and energy to invest in finding high-quality friends, making it likely that the nature of these preferences differs depending on the resources an individual has available to invest in this goal. Across two studies (total N = 693), we investigated how this trade-off may function by investigating the nature of friendship preferences. In Study 1, we utilized the budget paradigm method from behavioral economics to investigate the necessities and luxuries in friendship preferences. In Study 2, we replicated these preferences with a novel method and extended our investigation into understanding the hierarchical nature of these preferences. Taken together, our results provide a promising starting point for research investigating trade-offs between necessities and luxuries in friendship preferences. [ABSTRACT FROM AUTHOR]

Background: Physical activity (PA) mitigated psychological distress during the initial weeks of the COVID-19 pandemic, yet not much is known about whether PA had effects on stress in subsequent months. We examined the relationship between change over time in COVID-related stress and self-reported change in PA between March and July 2020. Methods: Latent growth modeling was used to examine trajectories of change in pandemic-related stress and test their association with self-reported changes in PA in an international sample (n = 679). Results: The participants reported a reduction in pandemic-related stress between April and July of 2020. Significant linear (factor mean = −0.22) and quadratic (factor mean = 0.02) changes (Ps <.001) were observed, indicating a deceleration in stress reduction over time. Linear change was related to change in PA such that individuals who became less active during the pandemic reported less stress reduction over time compared with those who maintained or increased their PA during the pandemic. Conclusions: Individuals who experienced the greatest reduction in stress over time during the pandemic were those who maintained their activity levels or became more active. Our study cannot establish a causal relationship between these variables, but the findings are consistent with other work showing that PA reduces stress. [ABSTRACT FROM AUTHOR]

COVID-19 was declared a global pandemic in March 2020. Resulting containment protocols altered the day-to-day lives of people around the globe, impacting typical physical activity patterns. The purpose of this mixed-method study was to understand how physical activity changes occurred during the first few months of the COVID-19 pandemic. Participants (n = 271) completed a survey including a qualitative item asking for descriptions of how their physical activity had changed, as well as a categorical item asking whether they had become more active, stayed equally as active, or become less active during the pandemic. Qualitative responses were analyzed to identify emergent themes, and chi-squared analyses were used to compare proportional differences in themes according to self-reported physical activity classification. Analysis revealed 10 themes: (1) decreased transportation-related physical activity, (2) change in location, (3) loss of resources, (4) discrepancies between self-reported changes in activity level and description of activities, (5) increased transportation-related physical activity, (6) changes in routines, (7) adapting exercise, (8) avoiding contact, (9) changes unrelated to COVID-19, and (10) illness or injury. Significant differences existed between groups for all themes except for avoiding contact, changes unrelated to COVID-19, and injury or illness. Empowering individuals to overcome barriers may be important during a pandemic to help people maintain or increase physical activity levels. Future research should explore the continued experience of people during the COVID-19 pandemic and investigate its impact on levels of physical activity going forward. [ABSTRACT FROM AUTHOR]

Understanding how genetics influences human psychology is something that the evolutionary sciences emphasize. However, the functions of complex genetic influences on behavior have been overlooked in favor of perspectives that posit unitary influences of genes on behavior. One such example is the belief that human growth, development, and behavior are influenced uniformly by their genes even though previous research has highlighted the genetic conflict endemic in these domains. Although much psychological research has robustly documented areas in which we see the footprints of genetic conflict in human behavior, these areas are referred to by different names that prevent researchers from making connections under a unifying framework. In this article, I outline what genetic conflict is and how genetic conflict can provide a unifying framework for psychological investigations of social relationships. I also discuss avenues for future research on genetic conflict in humans and the importance of considering cultural, ecological, and other developmental factors when researching the genetic influences on human behavior. [ABSTRACT FROM AUTHOR]

Because human patients with monkeypox virus (MPXV) infection report painful symptoms, it is reasonable to assume that animals infected with MPXV experience some degree of pain. Understanding whether and how analgesics affect MPXV disease progression is crucial when planning in vivo challenge experiments. In the current study, we challenged prairie dogs with a low dose (4 ×10³ pfu) of MPXV and treated with meloxicam (NSAID) or buprenorphine (opioid); control animals did not receive analgesia or received analgesia without MPXV challenge. Subsets of animals from each group were serially euthanized during the course of the study. Disease progression and viral kinetics were similar between groups, but MXPVinfected, meloxicam-treated animals showed increasing trends of morbidity and mortality compared with other groups. Differences between no-analgesia MPXV-infected control animals and MPXV-infected animals treated with buprenorphine were minimal. The findings in the current study allow more informed decisions concerning the use of analgesics during experimental MPXV challenge studies, thereby improving animal welfare. In light of these findings, we have modified our pain scale for this animal model to include the use of buprenorphine for pain relief when warranted after MPXV challenge.

Prions are proteinaceous infectious agents that are highly resistant to denaturation. Sterilization of prion-contaminated mouse cages requires chemical agents and increased autoclave temperatures that damage traditional cages, thus increasing facility costs. Disposable cages are a possible alternative that might decrease replacement costs without compromising the environment of the mice. We compared our standard protocol of changing traditional cages and bedding once every 2 wk to an experimental protocol using disposable cages in which only the bedding was changed once every 2 wk over an 8-wk period. We hypothesized that disposable cages would retain an acceptable level of cleanliness (measured by ATP swabs and contact plates) for at least 8 wk when bedding is replaced every 14 d. Results from ATP swabs and contact plates showed no difference between the 2 protocols during the 8-wk experiment. Prolonged use (that is, as long as 8 wk) of disposable cages had no additional environmental concerns, compared with traditional cages.

Alfaxalone encased in hydroxypropyl-β -cyclodextrin is a neuroactive steroid compound that has recently been approved in the United States for use as an anesthetic in dogs and cats. We evaluated the use of alfaxalone compared with ketamine, both alone and in combination with xylazine, for anesthesia of C57BL/6 mice. We assessed time to onset of anesthesia, duration of action, reflex responses, respiratory rate, and clinical signs. Alfaxalone (80 mg/kg IP) induced a light surgical plane of anesthesia in all mice, with a time to onset of 2.2 ± 0.2 min and duration of 57.1 ± 3.8 min, whereas ketamine (80 mg/kg IP) provided only sedative effects (time to onset, 5.4 ± 0.4 min; duration, 6.9 ± 0.8 min). Clinically, alfaxalone caused a spectrum of activities, including popcorn-like jumping movements after injection, intense scratching of the face, hyperresponsiveness to noise or touch, and marked limb jerking during recovery. Adding xylazine to the single-agent protocols achieved deep surgical anesthesia (duration: alfaxalone + xylazine, 80.3 ± 17.8 min; ketamine + xylazine, 37.4 ± 8.2 min) and ameliorated the adverse clinical signs. Our preliminary analysis suggests that, because of its side effects, alfaxalone alone is not a viable anesthetic option for mice. Although alfaxalone combined with xylazine appeared to be a more viable option, some mice still experienced mild adverse reactions, and the long duration of action might be problematic regarding the maintenance of body temperature and monitoring of recovery. Further studies evaluating different routes of administration and drug combinations are warranted.

Cotton rats (Sigmodon hispidus) are a valuable animal model for many human viral diseases, including polio virus, measles virus, respiratory syncytial virus, and herpes simplex virus. Although cotton rats have been used in research since 1939, few publications address handling and sampling techniques for this species, and the retroorbital sinus remains the recommended blood sampling site. Here we assessed blood sampling methods that are currently used in other species and a novel subzygomatic sampling site for their use in S. hispidus. The subzygomatic approach accesses a venous sinus that possibly is unique to this species and that lies just below the zygomatic arch of the maxilla and deep to the masseter muscle. We report that both the novel subzygomatic approach and the sublingual vein method can be used effectively in cotton rats.