A statistical framework for measuring the temporal stability of human mobility patterns.

Despite the growing popularity of human mobility studies that collect GPS location data, the problem of determining the minimum required length of GPS monitoring has not been addressed in the current statistical literature. In this paper, we tackle this problem by laying out a theoretical framework for assessing the temporal stability of human mobility based on GPS location data. We define several measures of the temporal dynamics of human spatiotemporal trajectories based on the average velocity process, and on activity distributions in a spatial observation window. We demonstrate the use of our methods with data that comprise the GPS locations of 185 individuals over the course of 18 months. Our empirical results suggest that GPS monitoring should be performed over periods of time that are significantly longer than what has been previously suggested. Furthermore, we argue that GPS study designs should take into account demographic groups.

Comparison of Bovine Small Antral Follicle Development in Two- and Three-Dimensional Culture Systems.

To compare the effects of two-(2D, microplate) and three-dimensional (3D, alginate) culture systems on the in vitro growth of small antral follicles in cattle, individual follicles were separately cultured in the two culture systems for 8 days. Half of the culture medium was replaced by fresh medium every 2 days; the former medium was used to assess the amount of follicular hormone secretion using ELISA. Individual follicle morphology, diameter, and survival rate were recorded every alternate day. The results showed that in 4 days, there was no significant difference between the two systems, except that the growth rate of follicles in 2D system was relatively faster. After 4 days, estradiol concentration in 3D system was higher than that in 2D system. However, progesterone concentration was lower than that in the 2D system. The survival rate and oocyte quality of follicles in 2D system were significantly lower than those in 3D system on day 8. The follicle diameter slightly increased (30-60 µm) in the entire process. Taken together, for in vitro culture of follicles within 4 days, the 2D culture system is more suitable. However, when the culture duration is >4 days, the 3D culture system is more suitable.

A cross-sectional study of social inequities in medical crowdfunding campaigns in the United States.

Americans are increasingly relying on crowdfunding to pay for the costs of healthcare. In medical crowdfunding (MCF), online platforms allow individuals to appeal to social networks to request donations for health and medical needs. Users are often told that success depends on how they organize and share their campaigns to increase social network engagement. However, experts have cautioned that MCF could exacerbate health and social disparities by amplifying the choices (and biases) of the crowd and leveraging these to determine who has access to financial support for healthcare. To date, research on potential axes of disparity in MCF, and their impacts on fundraising outcomes, has been limited. To answer these questions, this paper presents an exploratory cross-sectional study of a randomized sample of 637 MCF campaigns on the popular platform GoFundMe, for which the race, gender, age, and relationships of campaigners and campaign recipients were categorized alongside campaign characteristics and outcomes. Using both descriptive and inferential statistics, the analysis examines race, gender, and age disparities in MCF use, and tests how these are associated with differential campaign outcomes. The results show systemic disparities in MCF use and outcomes: people of color (and black women in particular) are under-represented; there is significant evidence of an additional digital care labor burden on women organizers of campaigns; and marginalized race and gender groups are associated with poorer fundraising outcomes. Outcomes are only minimally associated with campaign characteristics under users' control, such as photos, videos, and updates. These results corroborate widespread concerns with how technology fuels health inequities, and how crowdfunding may be creating an unequal and biased marketplace for those seeking financial support to access healthcare. Further research and better data access are needed to explore these dynamics more deeply and inform policy for this largely unregulated industry.