Precision capacitor has improved temperature and operational stability

Vacuum dielectric capacitor is fabricated from materials with very low temperature coefficients of expansion. This precision capacitor in the 1000-2000 picofarad range has a near-zero temperature coefficient of capacitance, eliminates ion chamber action caused by air ionization in the dielectric, and minimizes electromagnetic field charging effects

T Tauri variability in the context of the beat-frequency model

We examine the implications of a beat frequency modulated model of T Tauri accretion. In particular we show that measurements of the variability of accretion generated lines can be used in conjunction with existing photometry to obtain a measurement of the underlying photospheric and disc flux. This provides an independent way of checking spectral energy distribution modelling. In addition, we show how spectroscopy of T Tauri stars can reveal the inclination angle between the magnetic axis and the plane of the disc.Comment: uuencoded compressed postscript. The preprint is also available at http://www.ast.cam.ac.uk/preprint/PrePrint.htm

Intensity-Correlation Spectroscopy

A survey is given of techniques for spectroscopic analysis using intensity fluctuations. Particular attention is given to counting times, the role of macroscopic sources and detectors, and the electronic constraints placed on the observations

Laboratory and Plant: The Flow of Viscous Liquids Through Pipes

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Voice control of the space shuttle video system

A pilot voice control system developed at the Jet Propulsion Laboratory (JPL) to test and evaluate the feasibility of controlling the shuttle TV cameras and monitors by voice commands utilizes a commercially available discrete word speech recognizer which can be trained to the individual utterances of each operator. Successful ground tests were conducted using a simulated full-scale space shuttle manipulator. The test configuration involved the berthing, maneuvering and deploying a simulated science payload in the shuttle bay. The handling task typically required 15 to 20 minutes and 60 to 80 commands to 4 TV cameras and 2 TV monitors. The best test runs show 96 to 100 percent voice recognition accuracy

The Yin-Yang of Management: The Quest for Dynamic Equilibrium

MODERN ORGANIZATIONS inherently contain a wide variety of tensions that leaders must deal with every day: collaboration vs. control, individual vs. collective, flexibility vs. efficiency and profit vs. social responsibility, to name just a few. As environments become more fast paced and competitive, individual leaders’ responses to these tensions are a fundamental determinant of an organization’s fate. Contingency Theory offers one response to these tensions. Assuming that organizational systems are most effective when they achieve alignment or ‘fit’ amongst internal elements and with the external environment, this approach explores conditions for selecting among competing demands — for example, making choices between exploration and exploitation, and centralized vs. decentralized operations. In this article we will discuss an alternative approach to handling tensions: the Paradox Perspective explores how organizations can attend to competing demands simultaneously. Although choosing between competing tensions might aid shortterm performance, the Paradox Perspective argues that longterm sustainability requires continuous efforts to meet multiple, divergent demands

Monodisperse self-assembly in a model with protein-like interactions

We study the self-assembly behaviour of patchy particles with `protein-like' interactions that can be considered as a minimal model for the assembly of viral capsids and other shell-like protein complexes. We thoroughly explore the thermodynamics and dynamics of self assembly as a function of the parameters of the model and find robust assembly of all target structures considered. Optimal assembly occurs in the region of parameter space where a free energy barrier regulates the rate of nucleation, thus preventing the premature exhaustion of the supply of monomers that can lead to the formation of incomplete shells. The interactions also need to be specific enough to prevent the assembly of malformed shells, but whilst maintaining kinetic accessibility. Free-energy landscapes computed for our model have a funnel-like topography guiding the system to form the target structure, and show that the torsional component of the interparticle interactions prevents the formation of disordered aggregates that would otherwise act as kinetic traps.Comment: 11 pages; 10 figure