Does regulation help? The impact of California‘s AB5 on Gig Workers

There is a widespread debate over how gig workers should be classified. The passage of California Assembly Bill 5 (AB5) - a landmark legislation that aims to correct the misclassification of gig workers, has significant implications for workers, platforms, regulators, and the economy. In this research, leveraging the passage of AB5 as a shock for a natural experiment, we empirically investigate the impact of AB5 on gig workers in California to provide insights. With the data collected from a leading online labor market that connects clients and gig workers, we applied a Difference in Difference approach, and we found that the monthly earnings of gig workers in California, compared to those in other states, have a significantly higher increase after AB5 was signed into law. This effect stems from both increased daily earnings and increased working days. We discuss the implications for policymakers and platforms

Nomogram for Predicting Bone Development State of Female Children and Adolescents–A Fast Screening Approach Based on Pubes Stages for Growth and Development

Objective: To develop a nomogram for predicting bone development state (BDS) of female children and adolescents in a large scale.Methods: Four hundred forty-seven female students were designated as the training cohort to develop the predictive model, whereas 196 female students were used as the validation cohort to verify the established model. Bone age, height, body mass, body fat percentage, and secondary sexual characteristics were recorded, and BDS was determined with the chronological age and bone age. Multivariate logistic regression was conducted to determine the factors, and nomogram was developed and validated with the training and validation cohorts, respectively.Results: One hundred forty-seven female students were identified as BDS abnormal in the training cohort (32.9%), and 104 were determined in the validation cohort (53.1%). Age, height, weight, and pubes stage were selected for the predictive model. A nomogram was developed and showed a good estimation, with a C-index of 0.78 and a good calibration in the training cohort. Application of the nomogram to the validation cohort showed a similar C-index of 0.75 and a good calibration.Conclusion: A nomogram for predicting bone development was developed, which can provide a relatively good estimation of BDS for female children and adolescents in Chinese metropolis

Parental beliefs on play among 2-3-year-olds : a mixed-method study in coastal China

Play is widely regarded as beneficial to children’s development in the early years, but this belief is not universal. Chinese traditional culture, for instance, views children’s play as harmful, or at least unbeneficial. Chinese parents, affected by the interactions between globalization and localization, have been transforming their beliefs on play. This thesis examines parental beliefs about the value of play in two- and three-year-old children in three coastal cities in China (Fuzhou, Shenzhen, and Shanghai). A mixed-method research approach was employed in the three-study research. Study One developed a new scale Chinese Parent Play Beliefs Scale (CPPBS) and examined the relationship between parents’ play beliefs and their engagement in children’s play at home, using a sample of 483 parents of children (M = 36.48 months, SD = 4.86), in Fuzhou and Shenzhen. Exploratory and confirmatory factor analyses confirmed a two-factor construct of CPPBS—Play for Learning and Play for Fun—and regression and mediation models indicated parent involvement mediated the relationship between beliefs about Play for Learning and children’s engagement with (pre-) academic related play, but it did not mediate the relationship between beliefs about Play for Fun and children’s engagement with fantasy and entertainment play. Study Two investigated variations in parents’ play beliefs, and their relation to child outcomes, among 163 couples with two- and three-year-old children (M = 38.73 months, SD = 4.91), in Shenzhen. Cluster analysis revealed the existence of three groups of parents: (1) Traditional parents, who placed a high value on (pre-) academic activities, but a low value on free play; (2) Contemporary parents, who placed a high value on free play, but a low value on (pre-) academic activities; and, (3) Eclectic parents, who highly valued both (pre-) academic activities and free play. Hierarchical regressions showed that, compared with the two other clusters, Eclectic parents had children with better gross motor, socio-emotional, and overall development, after controlling for socio-demographic factors. Study Three was a multiple-case study in Shanghai that purposively selected six cases, of which two were representative of each cluster found in Study Two. The results verified the diversity of parents’ beliefs about children’s play, and the complexity of the relationship between parental play beliefs and practices found in Studies One and Two. Parental perceptions, values, and attitudes towards children’s play and learning varied among the six cases. The differences were mostly instantiated in family-based practices regarding the provision of toys, use of time, and parental roles in children’s play. However, some beliefs were not translated into action. This thesis systematically examined parental beliefs on early childhood play in Chinese contexts. Its findings provide empirical evidence about intra-cultural variations in the play beliefs of contemporary Chinese parents, and highlight the importance thereof for young children’s development of a balance in the home between free play and structured activities. Implications, limitations, and future research directions are discussed.published_or_final_versionEducationDoctoralDoctor of Philosoph

Parenting Stress, Parent–Child Literacy Activities, and Pre-Schoolers’ Reading Interest: The Moderation Role of Child Number in Chinese Families

China replaced the Two-Child Policy with the Three-Child Policy in 2021 to raise birth rates, but the potential effects of the increased number of children on family life and child development have not been empirically explored. This study examines the moderating role of child number in the relationships between parenting stress, parent–child literacy activities, and young children’s reading interest in the new Three-Child Policy context in China. A sample of 895 Chinese families was randomly recruited from a coastal city in southeastern China: one-child families (None-child = 359, Mage = 5.0, SD = 0.9), two-child families (Ntwo-child = 469, Mage = 5.1, SD = 0.9), and three-child and above families (Nthree-child and above = 67, Mage = 5.2, SD = 1.0). The participants completed the Parenting Stress Index-Short Form, the Parent-Child Literacy Activities Scale, and the Children’s Reading Interest Questionnaire. The results showed that (1) parents with more children had higher levels of parenting stress; (2) no significant differences existed in children’s reading interest between families with different numbers of children; (3) parent–child literacy activities mediated the relationship between parenting stress and children’s reading interest; (4) child number moderated the mediating effect of parent–child literacy activities in the relationship between parenting stress and children’s reading interest, even after adjusting for child age, gender, and family socioeconomic status (SES). Overall, this study demonstrated how the increased number of children would interact with the family system concerning early childhood literacy development

Beyond person-environment congruence: Career adaptability, career personality styles, and thinking styles

The main objectives of this study were to explore the relationship between career personality styles and career adaptability and the role of thinking styles in such relationship. Eight hundred and eleven Chinese students, who were trained as pre-service kindergarten teachers, responded to the Career Personality Styles Inventory, the shortened Thinking Styles Inventory-Revised, and the Career Adapt-Ability Scale – Short Form. Results suggested that the career personality styles (i.e. social, enterprising) that fit the vocational environment of kindergarten teaching the most positively predicted the students' career adaptability, both directly and indirectly through creativity-generating thinking styles. Moreover, the artistic and investigative career personality styles indirectly predicted students' career adaptability through creativity-generating thinking styles, while the conventional and realistic career personality styles showed no significant effect on the students' career adaptability. The findings imply that beyond the notion of person-environment congruence, some career personality styles can consistently predict career adaptability through thinking styles. Implications for career counseling and education practice are discussed

Propidium monoazide pretreatment on a 3D-printed microfluidic device for efficient PCR determination of 'live: Versus dead' microbial cells

Waterborne microbial pathogen detection via nucleic acid analysis on portable microfluidic devices is a growing area of research, development, and application. Traditional polymerase chain reaction (PCR)-based nucleic acid analysis detects total extracted DNA, but cannot differentiate live and dead cells. A propidium monoazide (PMA) pretreatment step before PCR can effectively exclude DNA from nonviable cells, as PMA can selectively diffuse through compromised cell membranes and intercalate with DNA to form DNA-PMA complex upon light exposure. The complex strongly inhibits the amplification of the bound DNA in PCR, and thus, only cells with intact cell membranes are detected. Herein, this study reports the development of a microfluidic device to carry out PMA pretreatment 'on-chip'. Chip design was guided by computer simulations, and prototypes were fabricated using a high-resolution 3D printer. The optimized design utilizes split and recombine mixers for initial PMA-sample mixing and a serpentine flow channel containing herringbone structures for dark and light incubation. On-chip PMA pretreatment to differentiate live and dead bacterial cells in buffer and natural pond water samples was successfully demonstrated