Identification and Exploitation of Inadvertent Spectral Artifacts in Digital Audio

We show that modulation products from local oscillators in a variety of commercial camcorders are coupled into the recorded audio track, creating narrow band time invariant spectral features. These spectral features, left largely intact by transcoding, compression and other forms of audiovisual post processing, can encode characteristics of specific camcorders used to capture the audio files, including the make and model. Using data sets both downloaded from YouTube and collected under controlled laboratory conditions we demonstrate an average probability of detection (Pd) approaching 0.95 for identification of a specific camcorder in a population of thousands of similar recordings, with a probability of false alarm (Pfa) of about 0.11. We also demonstrate an average Pd of about 0.93 for correct association of make and model of camcorder based on comparison of audio spectral features extracted from random YouTube downloads compared to a reference library of spectral features captured from known makes and models of camcorders, with a Pfa of 0.06. The method described can be used independently or synergistically with image plane-based techniques such as those based upon Photo Response Non-Uniformity

Steady state behaviour in atomic three-level lambda and ladder systems with incoherent population pumping

The steady state in three-level lambda and ladder systems is studied. It is well-known that in a lambda system this steady state is the coherent population trapping state, independent of the presence of spontaneous emission. In contrast, the steady state in a ladder system is in general not stable against radiative decay and exhibits a minimum in the population of the ground state. It is shown that incoherent population pumping destroys the stability of the coherent population trapping state in the lambda system and suppresses a previously discovered sharp dip in the steady state response. In the ladder system the observed minimum disappears in the presence of an incoherent pump on the upper transition.Comment: 4 pages, RevTex, 5 figures, to appear in Phys. Rev.

The coherent interaction between matter and radiation - A tutorial on the Jaynes-Cummings model

The Jaynes-Cummings (JC) model is a milestone in the theory of coherent interaction between a two-level system and a single bosonic field mode. This tutorial aims to give a complete description of the model, analyzing the Hamiltonian of the system, its eigenvalues and eigestates, in order to characterize the dynamics of system and subsystems. The Rabi oscillations, together with the collapse and revival effects, are distinguishing features of the JC model and are important for applications in Quantum Information theory. The framework of cavity quantum electrodynamics (cQED) is chosen and two fundamental experiments on the coherent interaction between Rydberg atoms and a single cavity field mode are described.Comment: 22 pages, 7 figures. Tutorial. Submitted to a special issue of EPJ - ST devoted to the memory of Federico Casagrand

Toward scalable quantum computation with cavity QED systems

We propose a scheme for quantum computing using high-Q cavities in which the qubits are represented by single cavity modes restricted in the space spanned by the two lowest Fock states. We show that single qubit operations and universal multiple qubit gates can be implemented using atoms sequentially crossing the cavities.Comment: 14 pages, 8 figure

Prevalence of Novel Candidate Sjogren Syndrome Autoantibodies in the Dry Eye Assessment and Management (DREAM) Study.

PurposeTo evaluate the prevalence of novel candidate Sjogren syndrome (SS) autoantibodies [salivary protein-1 (SP-1), parotid secretory protein, carbonic anhydrase 6] in the DRy Eye Assessment and Management (DREAM) cohort, a study evaluating the effectiveness of omega-3 fatty acid supplements for the treatment of dry eye.MethodsParticipants underwent ocular surface examinations and serological testing for traditional and novel SS autoantibodies. Dry eye assessment and management participants were categorized into the following 3 groups: 1) no history of SS or other autoimmune diseases and negative traditional SS autoantibodies (n = 352); 2) no history of SS but a history of other autoimmune diseases (n = 66); and 3) those who met the 2012 American College of Rheumatology SS classification criteria (n = 52).ResultsEleven percent had a history of SS, and 6% of those without a history of SS most likely had undiagnosed SS. The SS group had a higher prevalence of SP-1 autoantibodies than the group without SS or other autoimmune diseases (33% vs. 19%; P = 0.02) but had no difference in carbonic anhydrase 6 (P = 0.31) or parotid secretory protein autoantibodies (P = 0.33). Participants who were positive for the traditional autoantibodies alone or positive for both traditional and novel autoantibodies had the highest scores for corneal (P = 0.002) and conjunctival staining (P < 0.001).ConclusionsData from this multicenter, prospective study demonstrated that one of the novel candidate autoantibodies, SP-1, is associated with underlying SS and that novel autoantibodies may be associated with worse ocular surface disease. Future longitudinal studies are needed to evaluate their utility in screening patients with dry eye for SS

Studies of group velocity reduction and pulse regeneration with and without the adiabatic approximation

We present a detailed semiclassical study on the propagation of a pair of optical fields in resonant media with and without adiabatic approximation. In the case of near and on resonance excitation, we show detailed calculation, both analytically and numerically, on the extremely slowly propagating probe pulse and the subsequent regeneration of a pulse via a coupling laser. Further discussions on the adiabatic approximation provide many subtle understandings of the process including the effect on the band width of the regenerated optical field. Indeed, all features of the optical pulse regeneration and most of the intricate details of the process can be obtained with the present treatment without invoke a full field theoretical method. For very far off resonance excitation, we show that the analytical solution is nearly detuning independent, a surprising result that is vigorously tested and compared to numerical calculations with very good agreement.Comment: 13 pages, 15 figures, submitted to Phys. Rev.

Diversity of hard-bottom fauna relative to environmental gradients in Kongsfjorden, Svalbard

A baseline study of hard-bottom zoobenthos in relation to environmental gradients in Kongsfjorden, a glacial fjord in Svalbard, is presented, based on collections from 1996 to 1998. The total species richness in 62 samples from 0 to 30 m depth along five transects was 403 species. Because 32 taxa could not be identified to species level and because 11 species are probably new to science, the total number of identified species was 360. Of these, 47 species are new for Svalbard waters. Bryozoa was the most diverse group. Biogeographic composition revealed features of both Arctic and sub-Arctic properties of the fauna. Species richness, frequency of species occurrence, mean abundance and biomass generally decreased towards the tidal glaciers in inner Kongsfjorden. Among eight environmental factors, depth was most important for explaining variance in the composition of the zoobenthos. The diversity was consistently low at shallow depths, whereas the non-linear patterns of species composition of deeper samples indicated a transitional zone between surface and deeper water masses at 15–20 m depth. Groups of “colonial” and “non-colonial” species differed in diversity, biogeographic composition and distribution by location and depth as well as in relation to other environmental factors. “Non-colonial” species made a greater contribution than “colonial” species to total species richness, total occurrence and biomass in samples, and were more influenced by the depth gradient. Biogeographic composition was sensitive to variation of zoobenthic characteristics over the studied depth range. A list of recorded species and a description of sampling sites are presented

Matched Pulse Propagation in a Three-Level System

The B\"{a}cklund transformation for the three-level Maxwell-Bloch equation is presented in the matrix potential formalism. By applying the B\"{a}cklund transformation to a constant electric field background, we obtain a general solution for matched pulses (a pair of solitary waves) which can emit or absorb a light velocity solitary pulse but otherwise propagate with their shapes invariant. In the special case, this solution describes a steady state pulse without emission or absorption, and becomes the matched pulse solution recently obtained by Hioe and Grobe. A nonlinear superposition rule is derived from the B\"{a}cklund transformation and used for the explicit construction of two solitons as well as nonabelian breathers. Various new features of these solutions are addressed. In particular, we analyze in detail the scattering of "invertons", a specific pair of different wavelength solitons one of which moving with the velocity of light. Unlike the usual case of soliton scattering, the broader inverton changes its sign through the scattering. Surprisingly, the light velocity inverton receives time advance through the scattering thereby moving faster than light, which however does not violate causality.Comment: 20 pages, Latex, 12 eps figure files some comments and references are added. postscript file with 12 figures can be obtained at http://photon.kyunghee.ac.kr/~qhpark

The local economic development processes in low-income countries: the case of the metropolis of Chegutu in Zimbabwe

Local authorities are widely regarded as catalysts accelerating localised processes of economic development in industrialised countries but in low-income countries they are perceived as dysfunctional, inefficient and ineffective in meeting and addressing societal demands. This abstract view is however, not grounded in empirical research. As such, utilising the case of the metropolis of Chegutu a survey was designed to empirically explicate the economic processes militating its economic development. The findings are useful to policy-makers, local government authorities and management scholars. The study's unique contribution lies in its examination of the processes of local economic development in a low-income country