58,269 research outputs found

    Electronic phase-locked-loop speed control system is stable

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    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

    Reports on a Course for Prospective High School Mathematics Teachers

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    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

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    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

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

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    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

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    Design and development of synchronous servo loop control syste

    Electron Population Aging Models for Wide-Angle Tails

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    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

    Law\u27s Influence on Medicine and Medical Ethics

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    Incompressibility in finite nuclei and nuclear matter

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    The incompressibility (compression modulus) K0K_{\rm 0} of infinite symmetric nuclear matter at saturation density has become one of the major constraints on mean-field models of nuclear many-body systems as well as of models of high density matter in astrophysical objects and heavy-ion collisions. We present a comprehensive re-analysis of recent data on GMR energies in even-even 112124^{\rm 112-124}Sn and 106,100116^{\rm 106,100-116}Cd and earlier data on 58 \le A \le 208 nuclei. The incompressibility of finite nuclei KAK_{\rm A} is expressed as a leptodermous expansion with volume, surface, isospin and Coulomb coefficients KvolK_{\rm vol}, KsurfK_{\rm surf}, KτK_\tau and KcoulK_{\rm coul}. \textit{Assuming} that the volume coefficient KvolK_{\rm vol} is identified with K0K_{\rm 0}, the KcoulK_{\rm coul} = -(5.2 ±\pm 0.7) MeV and the contribution from the curvature term Kcurv_{\rm curv}A2/3^{\rm -2/3} in the expansion is neglected, compelling evidence is found for K0K_{\rm 0} to be in the range 250 <K0< < K_{\rm 0} < 315 MeV, the ratio of the surface and volume coefficients c=Ksurf/Kvolc = K_{\rm surf}/K_{\rm vol} to be between -2.4 and -1.6 and KτK_{\rm \tau} between -840 and -350 MeV. We show that the generally accepted value of K0K_{\rm 0} = (240 ±\pm 20) MeV can be obtained from the fits provided cc \sim -1, as predicted by the majority of mean-field models. However, the fits are significantly improved if cc is allowed to vary, leading to a range of K0K_{\rm 0}, extended to higher values. A self-consistent simple (toy) model has been developed, which shows that the density dependence of the surface diffuseness of a vibrating nucleus plays a major role in determination of the ratio Ksurf/Kvol_{\rm surf}/K_{\rm vol} and yields predictions consistent with our findings.Comment: 26 pages, 13 figures; corrected minor typos in line with the proof in Phys. Rev.