Microbiome preterm birth DREAM challenge: Crowdsourcing machine learning approaches to advance preterm birth research

Every year, 11% of infants are born preterm with significant health consequences, with the vaginal microbiome a risk factor for preterm birth. We crowdsource models to predict (1) preterm birth (PTB; \u3c37 \u3eweeks) or (2) early preterm birth (ePTB; \u3c32 \u3eweeks) from 9 vaginal microbiome studies representing 3,578 samples from 1,268 pregnant individuals, aggregated from public raw data via phylogenetic harmonization. The predictive models are validated on two independent unpublished datasets representing 331 samples from 148 pregnant individuals. The top-performing models (among 148 and 121 submissions from 318 teams) achieve area under the receiver operator characteristic (AUROC) curve scores of 0.69 and 0.87 predicting PTB and ePTB, respectively. Alpha diversity, VALENCIA community state types, and composition are important features in the top-performing models, most of which are tree-based methods. This work is a model for translation of microbiome data into clinically relevant predictive models and to better understand preterm birth

Ethanol as a Probe for the Mechanism of Bubble Nucleation in the Diet Coke and Mentos Experiment

The Diet Coke and Mentos experiment involves dropping Mentos candies into carbonated beverages to produce a fountain. This simple experiment has enjoyed popularity with science teachers and the general public. Studies of the physicochemical processes involved in the generation of the fountain have been largely informed by the physics of bubble nucleation. Herein, we probe the effect of ethanol addition on the Diet Coke and Mentos experiment to explore the impact that beverage surface tension and viscosity have on the heights of fountains achieved. Our results indicate that current descriptions of the effects of surface tension and viscosity are not completely understood. We also extend and apply a previously reported, simplified version of Brunauer–Emmett–Teller theory to investigate kinetic and mechanistic aspects of bubble nucleation on the surface of Mentos candies in carbonated beverages. A combination of this new theory and experiment allows for the estimation that the nucleation sites on the Mentos candy that catalyze degassing are 1–3 μm in size, and that between 50,000 and 300,000 of these sites actively nucleate bubbles on a single Mentos candy. While the methods employed are not highly sophisticated, they have potential to stimulate fresh investigations and insights into bubble nucleation in carbonated beverages

A Simple Chemical Oscillator: The Educator

A slightly modified version of Lotka\u27s mechanism that gives rise to sustained oscillations is shown to mimic observations of electrochemical oscillations reported during the dissolution of iron from iron electrodes in acidic media. The presentation of the modified mechanism includes only familiar chemical species and, in comparison to other mechanisms of chemical oscillators, is analyzed in a simple manner. Therefore, this new mechanism is particularly well-suited to present to students during introductory discussions on the topic of oscillating chemical reactions

Childhood Fitness: What Is Happening? What Needs to Be Done?

Background. There is some controversy as to the fitness levels of U.S. school-age youth. Some experts claim that U.S. youth are fit. Others feel that there has been a decline, despite a recent adult fitness boom. Methods. The purpose of this article is to examine the research conducted on the cardiovascular endurance and body composition levels of U.S. youth. Research studies noting the activity patterns of youth outside and during physical education are presented. The frequency and duration of physical education requirements are also reviewed. The effects of these patterns and requirements on cardiovascular endurance and body composition are presented. Results. U.S. youth do not engage in physical activity, within or outside physical education, sufficient to develop cardiovascular endurance. Our youth are, therefore, at risk of developing a myriad of diseases associated with sedentary lifestyles. Conclusions. Exercise is known to have a prophylactic effect on disease, death, and disability. Young people must be instructed and encouraged to be involved in lifetime fitness activities if we are going to control health care costs, reduce disease incidence, and improve the overall quality of life of our citizens.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/30720/1/0000366.pd

An exploration of cloud droplet growth by condensation and collision-coalescence in a convection-cloud chamber

Atmospheric clouds are crucial to weather and climate, and the rate at which droplets collide and coalesce to form precipitation is one of the fundamental controlling processes. The convection-cloud chamber allows the interactions between aerosols and cloud droplets produced by condensation to be investigated within a turbulent environment. Studying the full range of microphysical conditions in atmospheric clouds is not possible, however, unless conditions for droplet growth by collision and coalescence are also achieved. In this study, we explore the conditions favorable to collision-coalescence growth in convection-cloud chambers, extending previous work on steady-state droplet size distributions due to condensation alone. We obtain analytic expressions for cloud droplet collision-coalescence rates, and for the functional form of droplet size distributions themselves. We derive several scaling laws and demonstrate consistency between these theoretical results and Monte-Carlo simulations of growth and precipitation within a convection-cloud chamber. Finally, we gain insights into the role of external parameters such as injection rate, supersaturation forcing, and chamber height in controlling the strength of the collision-coalescence process, and the resulting shape of the droplet size distribution