Heterogeneity in Generational Effects: Case Study of Ride-hailing Behavior Among Millennials

This paper presents an investigation of the use and frequency of use of ride-hail services. In particular, we explored the role of generational effects and the heterogeneity involved in Millennials’ decision making when it comes to ride-hail choices. Using an ordered logistic regression structure, different statistical models were developed and tested, including fixed-effects and random parameter models, as well as the inclusion of interaction effects and attitudinal factors. Initial results from the fixed-effects model showed that the younger cohorts, including Millennials and Generation Z, showed a significantly positive preference for more frequent ride-hail use, whereas the older cohorts’ preferences (Generation X, Baby Boomers, and older) did not show any significant effects on ride-hail frequency. In the next step, the presence of heterogeneity among Millennials was tested using random parameters. The results confirmed that Millennials’ usage of ride-hail was heterogeneous, and this was statistically significant at the 90% confidence interval [Formula: see text]. To identify sources of heterogeneity, interaction effects were added to the model. Accordingly, use of ride-hail was more popular among middle-aged Millennials (30 to 34 years old) and Millennials with higher incomes. Likewise, attitudes such as cost sensitivity (toward private vehicle ownership), and being a rational user resulted in higher frequency ride-hail use across Millennials. On the contrary, unemployed Millennials were less likely to utilize ride-hail. The results from this study provide a more transparent picture of current ride-hail market segmentation, which could help predict the future market comprising autonomous vehicles and other emerging mobility options.

Parental ecological history can differentially modulate parental age effects on offspring physiological traits in Drosophila

Parents adjust their reproductive investment over their lifespan based on their condition, age, and social environment, creating the potential for inter-generational effects to differentially affect offspring physiology. To date, however, little is known about how social environments experienced by parents throughout development and adulthood influence the effect of parental age on the expression of life-history traits in the offspring. Here, I collected data on Drosophila melanogaster offspring traits (i.e., body weight, water content and lipid reserves) from populations where either mothers, fathers both or neither parents experienced different social environments during development (larval crowding) and adulthood. Parental treatment modulated parental age effects on offspring lipid reserves but did not influence parental age effects on offspring water content. Importantly, parents in social environments where all individuals were raised in uncrowded larval densities produced daughters and sons lighter than parental treatments which produced the heaviest offspring. The peak in offspring body weight was delayed relative to the peak in parental reproductive success, but more strongly so for daughters from parental treatments where some or all males in the parental social environments were raised in crowded larval densities (irrespective of their social context), suggesting a potential father-to-daughter effect. Overall, the findings of this study reveal that parental ecological history (here, developmental and adult social environments) can modulate the effects of parental age at reproduction on the expression of offspring traits.

Longitudinal evidence that older parents produce offspring with longer telomeres in a wild social bird

As telomere length (TL) often predicts survival and lifespan, there is considerable interest in the origins of inter-individual variation in TL. Cross-generational effects of parental age on offspring TL are thought to be a key source of variation, but the rarity of longitudinal studies that examine the telomeres of successive offspring born throughout the lives of parents leaves such effects poorly understood. Here, we exploit TL measures of successive offspring produced throughout the long breeding tenures of parents in wild white-browed sparrow weaver ( Plocepasser mahali ) societies, to isolate the effects of within-parent changes in age on offspring TLs. Our analyses reveal the first evidence to date of a positive within-parent effect of advancing age on offspring TL: as individual parents age, they produce offspring with longer telomeres (a modest effect that persists into offspring adulthood). We consider the potential for pre- and post-natal mechanisms to explain our findings. As telomere attrition predicts offspring survival to adulthood in this species, this positive parental age effect could impact parent and offspring fitness if it arose via differential telomere attrition during offspring development. Our findings support the view that cross-generational effects of parental age can be a source of inter-individual variation in TL.

Null Direct Object Clitics in Basque Spanish: A Study Across Four Generations

The null direct object clitic is described as one of the distinctive morphosyntactic features of Basque Spanish (e.g., compré el libro i , pero se me ha olvidado traer øi). However, no study to date has explored the variable usage of this form in cross-generational terms. The present inquiry aims to fill this void by analyzing and contrasting the results of two studies by four generations of Spanish-Basque bilinguals with the following age ranges: 85–96 (Generation 1), 55–75 (Generation 2), 35–45 (Generation 3), 18–25 (Generation 4). The education level of the participants was also taken into consideration. The first study consisted of an acceptability judgment task, in which the participants rated the acceptability of sentences with a null direct object using a 5-point Likert scale. The independent linguistic variables in this study were the semantic features [+/-definiteness] and [+/-specificity]. The acceptance rate of null direct object clitics was significantly higher among Generation 1 and 2 speakers than among those of Generation 3 and 4, with no effect of definiteness or specificity. In the second study, based on an elicitation task, older speakers (Generation 1 and 2) produced significantly more null direct object clitics than their younger counterparts (Generation 3 and 4). By contrasting the differential behavior of the participants across and within the same generation, it is shown that the generational effects observed are mainly due to the participants’ different levels of formal education.

Beyond Slacktivism: The Cases of K-pop Fans and Tiktok Teens

With recent technology and social media, new forms of political activism have become widespread. Young people in particular, have been willing to embrace these new forms of activism. This paper examines new trends in digital activism through qualitative observations of Twitter and Tiktok, and three case studies of young people’s digital activism. In the first case study, Korean pop music (K-pop) fans thwarted police’s attempts to identify protesters by crashing police apps. In the second, they rendered white supremacist hashtags useless, by drowning out the hashtags with their own tweets. Finally, K-pop fans, along with Tiktok users, played a prank which humiliated the Trump reelection campaign. The study expands upon the life cycle effect and generational effects theories of political behavior, and develops a continuum with which to conceptualize and understand the nature of activism. It concludes that digital activism is characteristic of Gen Z, and has real-world impacts. This article pushes back on the notion that digital activism is mere “slacktivism” (low effort token support of a social movement). Instead, it argues that activism evolves along with technology and time, and that digital activism’s real-world impacts can be just as effective as conventional political activism.

Intergenerational Transmission of Resistance of Callosobruchus maculatus to Essential Oil Treatment

Due to the rise of numerous legal restrictions as well as the increasing emergence of resistant populations, the number of available pesticides is decreasing significantly. One of the potential alternatives often described in the literature are essential oils (EOs). However, there is a lack of research addressing the potential emergence of resistance to this group of substances. In this paper, we investigated the multi-generational effects of sublethal concentrations of rosemary oil (Rosmarinus officinalis) on physiological and biochemical parameters of the cowpea weevil (Callosobruchus maculatus) such as egg laying, hatchability, oxygen consumption and acetylcholinesterase activity. Imago, which as larvae were exposed to EO at concentrations equivalent to LC25, showed significantly lower mortality. The results obtained indicate the potential development of resistance in insects exposed to EO in concentrations corresponding to LC25. In addition, in the case of the group treated with an EO concentration corresponding to LC3.12, a stimulation effect of the above-mentioned parameters was observed, which may indicate the occurrence of a hormesis effect. The obtained results may be an important reference for the development of future guidelines and EO-based insecticides.