Exploring prenatal testing preferences among US pregnant individuals: A discrete choice experiment

Although there are numerous benefits to diagnostic prenatal testing, such as fetal exome sequencing, there are also consequences, including the possibility of receiving variants of uncertain significance or identifying secondary findings. In this study, we utilized a survey-based discrete choice experiment to elicit the preferences of pregnant people in Northern California for hypothetical prenatal genomic tests. Pregnant individuals were invited to complete the survey through advertisements on social media. Five test attributes were studied: likelihood of getting a result, time taken to receive results, who explains results, reporting of uncertain results, and reporting of secondary findings. The survey also gathered information about the participants' demographics, current and past pregnancies, and tolerance of uncertainty using the IUS-12 scale. Participants were eligible if they were female, currently 24 or more weeks pregnant, and able to read/write enough English or Spanish to complete an online survey. Overall, participants (n = 56) preferred the option of having a prenatal test over not having a prenatal test (p < 0.01) and had substantially higher preferences for tests with the highest likelihood of getting a result (p < 0.01). There were also positive preferences for tests that reported secondary findings (p = 0.01) and those where results were returned by a genetic specialist (vs. their prenatal provider) (p = 0.04). These findings can be used to guide conversations between pregnant individuals and genetics specialists, such as genetic counselors, as they weigh the pros and cons of diagnostic prenatal testing options

Fluctuations in spo0A Transcription Control Rare Developmental Transitions in Bacillus subtilis

Phosphorylated Spo0A is a master regulator of stationary phase development in the model bacterium Bacillus subtilis, controlling the formation of spores, biofilms, and cells competent for transformation. We have monitored the rate of transcription of the spo0A gene during growth in sporulation medium using promoter fusions to firefly luciferase. This rate increases sharply during transient diauxie-like pauses in growth rate and then declines as growth resumes. In contrast, the rate of transcription of an rRNA gene decreases and increases in parallel with the growth rate, as expected for stable RNA synthesis. The growth pause-dependent bursts of spo0A transcription, which reflect the activity of the spo0A vegetative promoter, are largely independent of all known regulators of spo0A transcription. Evidence is offered in support of a “passive regulation” model in which RNA polymerase stops transcribing rRNA genes during growth pauses, thus becoming available for the transcription of spo0A. We show that the bursts are followed by the production of phosphorylated Spo0A, and we propose that they represent initial responses to stress that bring the average cell closer to the thresholds for transition to bimodally expressed developmental responses. Measurement of the numbers of cells expressing a competence marker before and after the bursts supports this hypothesis. In the absence of ppGpp, the increase in spo0A transcription that accompanies the entrance to stationary phase is delayed and sporulation is markedly diminished. In spite of this, our data contradicts the hypothesis that sporulation is initiated when a ppGpp-induced depression of the GTP pool relieves repression by CodY. We suggest that, while the programmed induction of sporulation that occurs in stationary phase is apparently provoked by increased flux through the phosphorelay, bet-hedging stochastic transitions to at least competence are induced by bursts in transcription

Vibration suppression, stabilization, motion planning and tracking for flexible beams

The problems of vibration suppression, stabilization, motion planning, and tracking for flexible beams are important for many practical mechanical systems, such as the cantilevered beam in an atomic force microscope, a solar panel array on a satellite, the boom on a crane, or a structure mounted on a shake table. This work approaches the aforementioned control design problems using two methods; backstepping for partial differential equations (PDEs), and extremum seeking. PDE backstepping is a form of model reference control for infinite dimensional systems where boundary control is used to make a closed- loop system perform like a target system, which is the reference model with desirable performance characteristics. Infinite dimensional state transformations, relating plant and target systems, are the key to PDE backstepping designs and are used to find the desired boundary controllers. PDE backstepping techniques are presented for motion planning and tracking for the string and shear beam with Kelvin-Voigt (KV) damping, and a combination of PDE backstepping and gain scheduling is presented for extending linear PDE backstepping techniques to stabilization, motion planning, and tracking for the string and shear beam with KV damping and boundary-displacement dependent free-end nonlinearities. Explicit motion planning reference solutions for the shear beam are found, using backstepping transformations, as a function of the target system reference solution, which itself is a function of the string solution. The string solution is the easiest to find, and is done using traditional motion planning tools. Tracking controllers are found as a combination of vibration suppression and motion planning controllers. Gain scheduling is a method that replaces nonlinear control design with the design of a family of linear controllers. When combined with linear PDE backstepping techniques, it provides a means of extending vibration suppression, stabilization, motion planning and tracking results to the string and shear beam with free-end nonlinearities. Gain scheduling based designs, which produce locally stabilizing controllers parameterized by a function of the nonlinearity, are a more simple and manageable alternative to full-state feedback linearizing nonlinear PDE control designs. Extremum seeking (ES) is a non-model based method used for tuning parameter(s) to optimize an unknown nonlinear map. ES tuning for positive- position-feedback compensators is presented as a method of selecting the parameter(s) of the compensator to improve vibration suppression on a mechanical system forced by a persistent sinusoidal disturbance. ES tuning for motion planning and tracking is presented as a method for tuning the amplitude and phase of a sinusoidal input to a stable linear plant to generate and track a sinusoid of desired amplitude and phase at the outpu