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Bringing the economy back in: Hannah Arendt, Karl Marx, and the politics of capitalism
No full textThis article engages with the question of how to construct modern economic relations as an object of political theorizing by placing Hannah Arendt's and Karl Marx's writings in critical conversation. I contend that the political aspect of capitalism comes into sharpest relief less in relations of economic exploitation than in moments of expropriation that produce and reproduce the conditions of capitalist accumulation. To develop a theoretical handle on expropriation and thereby on the politics of capitalism, I syncretically draw on Marxian and Arendtian concepts by first examining expropriation through the Marxian analytic of "primitive accumulation of capital" and second delineating the political agency behind primitive accumulation through the Arendtian notion of "power." I substantiate these connections around colonial histories of primitive accumulation wherein expropriation emerges as a terrain of political contestation. From this perspective I conclude that such putatively "economic" questions as dispossession, exploitation, and accumulation appear as irreducibly political questions
Resonant light coupling to microspheres using Gaussian beams of optical fibers
No full textMorphology dependent resonances of dielectric microspheres are used for polarization insensitive optical channel dropping from an optical fiber half coupler to a silicon photodetector in the M-band. The dropped channels are observed in the elastic scattering and the transmission spectra. The highest quality factor morphology dependent resonances have a repetitive channel separation of 0.14 nm and a linewidth of 0.06 nm. The filter drops approximately 10% (0.5 dB) of the power at the resonance wavelength. The power detected by the photodiode is estimated to be approximately 3.5% of the power in the fiber
The long-term stock market valuation of customer satisfaction
No full textFirm valuation has been an important domain of interest for finance. However, most financial models do not include customer-related metrics in this process. Studies in marketing have found that one particular customer metric, customer satisfaction, improves the ability to predict future cash flows, long-term financial measures, stock performance, and shareholder value. However, most of these studies predominantly employ models that are not directly used in finance practice. This article extends existing literature by examining the impact of customer satisfaction on firm valuation by employing multiples and risk-adjusted abnormal return models borrowed directly from the practice of finance. Data include 3600 firm-quarter observations from the American Customer Satisfaction Index, COMPUSTAT, and Center for Research in Securities Prices databases from 1996 to 2006. The results indicate that a portfolio of stocks consisting of firms with high levels and positive changes in customer satisfaction will outperform the other three possible portfolio combinations (low levels and negative changes, low levels and positive changes, and high levels and negative changes in customer satisfaction) along with Standard & Poor's 500. Initially, the stock market undervalues positive satisfaction information, but the market adjusts in the long run
HotSprint: database of computational hot spots in protein interfaces
No full textWe present a new database of computational hot spots in protein interfaces: HotSprint. Hot spots are residues comprising only a small fraction of interfaces yet accounting for the majority of the binding energy. HotSprint contains data for 35 776 protein interfaces among 49 512 protein interfaces extracted from the multi-chain structures in Protein Data Bank (PDB) as of February 2006. The conserved residues in interfaces with certain buried accessible solvent area (ASA) and complex ASA thresholds are flagged as computational hot spots. The predicted hot spots are observed to correlate with the experimental hot spots with an accuracy of 76. Several machine-learning methods (SVM, Decision Trees and Decision Lists) are also applied to predict hot spots, results reveal that our empirical approach performs better than the others. A web interface for the HotSprint database allows users to browse and query the hot spots in protein interfaces; and it provides information for interface residues that are functionally and structurally important as well as the evolutionary history and solvent accessibility of residues in interfaces
Generalized adiabatic product expansion: a nonperturbative method of solving the time-dependent Schrodinger equation
No full textWe outline a method based on successive canonical transformations which yields a product expansion for the evolution operator of a general (possibly non-Hermitian) Hamiltonian. For a class of such Hamiltonians this expansion involves a finite number of terms, and our method gives the exact solution of the corresponding time-dependent Schrödinger equation. We apply this method to study the dynamics of a general nondegenerate two-level quantum system, a time-dependent classical harmonic oscillator, and a degenerate system consisting of a spin 1 particle interacting with a time-dependent electric field ℰ→(t) through the Stark Hamiltonian H = λ(J→ · ℰ→)2
Pseudo-Hermiticity versus PT-symmetry III: equivalence of pseudo-Hermiticity and the presence of antilinear symmetries
No full textWe show that a diagonalizable (non-Hermitian) Hamiltonian H is pseudo-Hermitian if and only if it has an antilinear symmetry, i.e., a symmetry generated by an invertible antilinear operator. This implies that the eigenvalues of H are real or come in complex conjugate pairs if and only if H possesses such a symmetry. In particular, the reality of the spectrum of H implies the presence of an antilinear symmetry. We further show that the spectrum of H is real if and only if there is a positive-definite inner-product on the Hilbert space with respect to which H is Hermitian or alternatively there is a pseudo-canonical transformation of the Hilbert space that maps H into a Hermitian operator
Drivers of chorus in the outer dayside magnetosphere
No full textUsing ELF/VLF wave data recorded in 2007 from two high-latitude (Lambda = 69.8 degrees, 71.8 degrees) Antarctic ground stations, the dayside variation of chorus wave occurrence and amplitude are analyzed in conjunction with geomagnetic and solar wind driving parameters. Both stations observe chorus (defined here as discrete rising emission tones together with unstructured hiss) in a broad window of local time across the dayside when the stations are on closed magnetic field lines. Wave occurrence rates rise rapidly from similar to 0.06-0.12 at dawn to their maximum value of similar to 0.5-0.6 near local noon. The event amplitudes also peak near noon. Occurrence probabilities at the lower-latitude station are consistently higher with the average difference in the rate between the two stations being 0.15. In addition, similar to 80% of the time, event amplitudes are larger at the lower-latitude site. When the stations are in the dawn local time sector (5.5 < MLT < 10), the onset of waves is clearly linked to substorms, as seen by the AE index as well as by energetic electron injections observed at geosynchronous orbit. However, as the stations rotate to noon (MLT > 10), wave occurrence rates appear to be relatively independent of geomagnetic activity as measured by K-p and AE. Chorus near noon at times appears related to substorm activity, but intense waves can also be observed during extended quiet periods. Waves across the entire dayside are more likely during higher solar wind dynamic pressure as well as during significant changes in pressure. We attribute the high occurrence rate of outer dayside chorus to several effects resulting from solar wind compression of the dayside magnetosphere; the first is electron drift shell splitting, and the second is the creation of a region of high magnetic field homogeneity which is particularly favorable for wave growth
On the occurrence of ground observations of ELF/VLF magnetospheric amplification induced by the HAARP facility
No full textThe ionospheric heating facility of the High Frequency Active Auroral Research Program (HAARP) has been used extensively in the last 3 years for injection of ELF/VLF waves into the magnetosphere via modulated heating of the overhead auroral electrojet currents. Of particular interest are waves that are observed to be nonlinearly amplified after interaction with hot plasma electrons in the Earth's radiation belts. Past results have shown HAARP to be an effective platform for controlled studies of wave particle interactions in the Earth's magnetosphere. A summary of the experimental results is provided in the context of dependencies on geomagnetic conditions and transmitter parameters. It is deduced that the primary variable that is associated with successful ground observations of HAARP-induced magnetospheric amplification is availability of magnetospheric wave guiding structures. Such structures are found to be most prevalent under quiet geomagnetic conditions following a disturbance when the plasmapause extends to the latitude of the HAARP facility or higher. Strong electrojet currents and high amplitudes of generated ELF/VLF signals observed on the ground are poor indicators of observation probability on a day to day basis although variation of these variables can be important on minute and second timescales. Frequency-time formats with continuously increasing ELF/VLF frequency show preferential amplification as predicted by nonlinear theory of electron trapping. Amplification of signals is also found to be possible for signals with noncoherent bandwidths of up to 30 Hz
Wave normal angles of magnetospheric chorus emissions observed on the Polar spacecraft
No full textUsing data from the High Frequency Waveform Receiver on board the Polar spacecraft, 1,765 and 993 wave normal angles have been analyzed for 13 orbits containing upper band magnetospheric chorus emissions and 15 orbits containing lower band emissions, respectively. The purpose of this study is to characterize the distribution of the polar wave normal angle, theta, for chorus emissions as a function of magnetic latitude, l. Understanding wave normal angles is an important step in evaluating resonant wave particle interactions. For upper band chorus, wave normal angles tend to remain at or rise toward the resonance cone angle for low latitudes and midlatitudes but move away from the resonance cone angle at higher latitudes. For lower band chorus, wave normal angles with values theta < 20 degrees have the highest probability of occurrence in the latitude range of 10 degrees-50 degrees. Just off the equator, 10 degrees <= lambda < 25 degrees, there exists a secondary occurrence peak in the range of 50 degrees <= theta < 70 degrees. The probability of observing these higher wave normal angles decreases with increasing latitude. The time-averaged Poynting flux, S, is much larger for lower band chorus waves, which have a mean value of 8.5 x 10(-8) W/m(2), than for upper band chorus waves, which have a mean value of 1.4 x 10(-9) W/m(2). S is fairly evenly distributed about its median value, 3.1 x 10(-10) W/m(2), for all wave normal angles for upper band chorus but deceases as theta increases for lower band chorus
Morphology-dependent resonances of optical microsphere resonators for the realization of passive wavelength-division multiplexing components
No full textMorphology-dependent resonances of microspheres can provide the necessary optical feedback for applications in spectroscopy, laser science, and optical communications. The elastic scattering of focused light from dielectric microspheres is understood by the localization principle and the generalized Lorenz-Mie theory. We excited the morphology-dependent resonances of glass microspheres by a tunable distributed-feedback laser and detected the elastically scattered signal. Efficient coupling to morphology-dependent resonances is achieved using an optical fiber half coupler. Resonance peaks in the elastic scattering spectra and associated dips in the transmission spectra are observed experimentally. Simulation results of elastic scattering spectra of glass microspheres in the C-band are presented. (C) 2004 Society of Photo-Optical Instrumentation Engineers