452,859 research outputs found
Going from Theory to Practice: The Mixed Success of Approval Voting
Approval voting (AV) is a voting system in which voters can vote for, or approve of, as many candidates as they like in multicandidate elections. In 1987 and 1988, four scientific and engineering societies, collectively comprising several hundred thousand members, used AV for the first time. Since then, about half a dozen other societies have adopted AV. Usually its adoption was seriously debated, but other times pragmatic or political considerations proved decisive in its selection. While AV has an ancient pedigree, its recent history is the focus of this paper. Ballot data from some of the societies that adopted AV are used to compare theoretical results with experience, including the nature of voting under AV and the kinds of candidates that are elected. Although the use of AV is generally considered to have been successful in the societies-living up to the rhetoric of its proponents-AV has been a controversial reform. AV is not currently used in any public elections, despite efforts to institute it, so its success should be judged as mixed. The chief reason for its nonadoption in public elections, and by some societies, seems to be a lack of key "insider" support.APPROVAL VOTING; ELECTIONS; PROFESSIONAL SOCIETIES; CONDORCET CANDIDATE.
Standing Alfven wave current system at Io: Voyager 1 observations
The enigmatic control of the occurrence frequency of Jupiter's decametric emissions by the satellite Io is explained theoretically on the basis of its strong electrodynamic interaction with the corotating Jovian magnetosphere leading to field aligned currents connecting Io with the Jovian ionosphere. Direct measurements of the perturbation magnetic fields due to this current system were obtained by the magnetic field experiment on Voyager 1 on 5 March 1979 when it passed within 20,500 km south of Io. An interpretation in the framework of Alfven waves radiated by Io leads to current estimates of 2.8 million amps. A mass density of 7400 to 13600 proton mass units per Cu cm is derived which compares very favorably with independent observations of the torus composition characterized by 7-9 proton mass units per electron for a local electron density of 1050 to 1500 per cu cm. The power dissipated in the current system may be important for heating the Io heavy ion torus, inner magnetosphere, Jovian ionosphere, and possibly the ionosphere or even the interior of Io
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Ultrafast, dual common cathode, epitaxial rectifier diode in a SOT186A (TO-220F)) plastic package
Voter Sovereignty and Election Outcomes
APPROVAL VOTING; ELECTIONS; CONDORCET WINNER/LOSER; NASH EQUILIBRIUM.
L'image toxicologique à Byzance: Fonctions et usages des miniatures des "Alexipharmaka" et des "Thèriaka" des pseudo-Dioscoride durant les derniers siècles de l'Empire
Results of long-term synoptic monitoring of Jupiter's decametric radiation
Results of the analysis of the large, homogeneous set of measurements of Jupiter's emission at 16.7 and 22.2 MHz for the apparitions during the period 1966-1974 were presented. An update of the radio rotation period determination which includes provision for beaming effects due to variations in the Jovicentric declination of the earth was presented. Some estimates of the magnitude of possible long-term variations in the rotation period were also discussed. The data clearly shows the Io-independent emission features associated with the System III central meridian longitudes of all three major Io-related source regions. There is also some evidence for heretofore unrecognized Io-related emission features which are apparently independent of the central meridian longitude. The possibility of three kinds of emission are suggested: (1) Io-stimulated, sharply beamed emission, (2) Io-independent, sharply beamed emission, and (3) Io-stimulated, broadly beamed emission
Models of bright nickel-free supernovae from stripped massive stars with circumstellar shells
The nature of an emerging class of rapidly fading supernovae
(RFSNe)--characterized by their short-lived light curve duration, but varying
widely in peak brightness--remains puzzling. Whether the RFSNe arise from
low-mass thermonuclear eruptions on white dwarfs or from the core collapse of
massive stars is still a matter of dispute. We explore the possibility that the
explosion of hydrogen-free massive stars could produce bright but rapidly
fading transients if the effective pre-supernova radii are large and if little
or no radioactive nickel is ejected. The source of radiation is then purely due
to shock cooling. We study this model of RFSNe using spherically symmetric
hydrodynamics and radiation transport calculations of the explosion of stripped
stars embedded in helium-dominated winds or shells of various masses and
extent. We present a parameter study showing how the properties of the
circumstellar envelopes affect the dynamics of the explosion and can lead to a
diversity of light curves. We also explore the dynamics of the fallback of the
innermost stellar layers, which might be able to remove radioactive nickel from
the ejecta, making the rapid decline in the late time light curve possible. We
provide scaling relations that describe how the duration and luminosity of
these events depend on the supernova kinetic energy and the mass and radius of
the circumstellar material.Comment: 16 pages, 17 figures, accepted to MNRA
NMDA Currents Modulate the Synaptic Input–Output Functions of Neurons in the Dorsal Nucleus of the Lateral Lemniscus in Mongolian Gerbils
Neurons in the dorsal nucleus of the lateral lemniscus (DNLL) receive excitatory and inhibitory inputs from the superior olivary complex (SOC) and convey GABAergic inhibition to the contralateral DNLL and the inferior colliculi. Unlike the fast glycinergic inhibition in the SOC, this GABAergic inhibition outlasts auditory stimulation by tens of milliseconds. Two mechanisms have been postulated to explain this persistent inhibition. One, an “integration-based” mechanism, suggests that postsynaptic excitatory integration in DNLL neurons generates prolonged activity, and the other favors the synaptic time course of the DNLL output itself. The feasibility of the integration-based mechanism was tested in vitro in DNLL neurons of Mongolian gerbils by quantifying the cellular excitability and synaptic input–output functions (IO-Fs). All neurons were sustained firing and generated a near monotonic IO-F on current injections. From synaptic stimulations, we estimate that activation of approximately five fibers, each on average liberating ∼18 vesicles, is sufficient to trigger a single postsynaptic action potential. A strong single pulse of afferent fiber stimulation triggered multiple postsynaptic action potentials. The steepness of the synaptic IO-F was dependent on the synaptic NMDA component. The synaptic NMDA receptor current defines the slope of the synaptic IO-F by enhancing the temporal and spatial EPSP summation. Blocking this NMDA-dependent amplification during postsynaptic integration of train stimulations resulted into a ∼20% reduction of the decay time course of the GABAergic inhibition. Thus, our data show that the NMDA-dependent amplification of the postsynaptic activity contributes to the GABAergic persistent inhibition generated by DNLL neurons
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