Reports on a Course for Prospective High School Mathematics Teachers

The author describes his design for a course entitled Secondary School Mathematics from an Advanced Viewpoint. He adds subjective comments on how his design has worked in practice

Parental Conversation Styles and Learning Science With Preschoolers

Preschool children participated in a science-learning event about light in their own classroom. The same day as the event, parents or caregivers were instructed to converse with their children at home in the evening about either the science learning event or another ‘special or fun’ event that happened to them recently in whatever way was natural for them. One week later, a researcher interviewed children to examine what they remembered about the science-learning event. Analyses focused on the impact of the topic and degree of elaboration of parent-child conversations on children’s memory for the science-learning event a week later. The findings have implications for best practices in preschool education

Electronic phase-locked-loop speed control system is stable

Phase locked-loop circuit is used for playback motors in digital tape recorders where the reproducer output remains in exact synchronism with an external reference clock over extended periods. It removes the motor dynamics from the control loop so that the loop is stable without damping

Totally Class-Less?: Examining Bristol-Myer\u27s Applicability to Class Actions

In June 2017, the U.S. Supreme Court tightened the specific jurisdiction doctrine when it dismissed several plaintiffs’ claims in a mass tort action against pharmaceutical company Bristol-Myers Squibb (BMS) for lack of personal jurisdiction. The action was brought in a California state court and involved several hundred plaintiffs alleging that they were injured by Plavix, a drug BMS manufactures. The Supreme Court held that California could not constitutionally exercise personal jurisdiction over BMS as to the nonresident plaintiffs, who did not have an independent connection to California. While the nonresident plaintiffs argued that California had specific jurisdiction because their claims were identical to the California residents’ claims (with the only difference being that their experience with Plavix occurred in other states), the Court held that these claims did not arise out of BMS’s contacts with California, but rather out of BMS’s contacts with the particular states in which these plaintiffs were injured. In so holding, the Court emphasized that enabling California to exercise jurisdiction in this context would infringe on the sovereignty of other states—more specifically, the states who housed the nonresident plaintiffs involved in the action. This Note explores whether class actions should be bound by this decision. The fundamental question, then, is whether class actions are meaningfully distinguishable from mass tort actions such that they avoid Bristol-Myers’s reach

Synchronous servo loop control system Patent

Design and development of synchronous servo loop control syste

Burdens and Restrictions of Workplace Regulations on Small Business: Statement of the U.S. Chamber of Commerce Before the Commission on the Future of Worker-Management Relations

Testimony_Stone_121593.pdf: 276 downloads, before Oct. 1, 2020

Electron Population Aging Models for Wide-Angle Tails

Color-color diagrams have been useful in studying the spectral shapes in radio galaxies. At the workshop we presented color-color diagrams for two wide-angle tails, 1231+674 and 1433+553, and found that the standard aging models do not adequately represent the observed data. Although the JP and KP models can explain some of the observed points in the color-color diagram, they do not account for those found near the power-law line. This difficulty may be attributable to several causes. Spectral tomography has been previously used to discern two separate electron populations in these sources. The combination spectra from two such overlying components can easily resemble a range of power-laws. In addition, any non-uniformity in the magnetic field strength can also create a power-law-like spectrum. We will also discuss the effects that angular resolution has on the shape of the spectrum.Comment: 4 pages, 1 figure, proceedings from 1999 'Life Cycles of Radio Galaxies' workshop at STScI in Baltimore, M

Simulation from endpoint-conditioned, continuous-time Markov chains on a finite state space, with applications to molecular evolution

Analyses of serially-sampled data often begin with the assumption that the observations represent discrete samples from a latent continuous-time stochastic process. The continuous-time Markov chain (CTMC) is one such generative model whose popularity extends to a variety of disciplines ranging from computational finance to human genetics and genomics. A common theme among these diverse applications is the need to simulate sample paths of a CTMC conditional on realized data that is discretely observed. Here we present a general solution to this sampling problem when the CTMC is defined on a discrete and finite state space. Specifically, we consider the generation of sample paths, including intermediate states and times of transition, from a CTMC whose beginning and ending states are known across a time interval of length $T$. We first unify the literature through a discussion of the three predominant approaches: (1) modified rejection sampling, (2) direct sampling, and (3) uniformization. We then give analytical results for the complexity and efficiency of each method in terms of the instantaneous transition rate matrix $Q$ of the CTMC, its beginning and ending states, and the length of sampling time $T$. In doing so, we show that no method dominates the others across all model specifications, and we give explicit proof of which method prevails for any given $Q,T,$ and endpoints. Finally, we introduce and compare three applications of CTMCs to demonstrate the pitfalls of choosing an inefficient sampler.Comment: Published in at http://dx.doi.org/10.1214/09-AOAS247 the Annals of Applied Statistics (http://www.imstat.org/aoas/) by the Institute of Mathematical Statistics (http://www.imstat.org