Low-frequency microwave radiometer for N-ROSS

The all weather, global determination of sea surface temperature (SST) has been identified as a requirement needed to support naval operations. The target SST accuracy is + or - 1.0 K with a surface resolution of 10 km. Investigations of the phenomenology and technology of remote passive microwave sensing of the ocean environment over the past decade have demonstrated that this objective is presently attainable. Preliminary specification and trade off studies were conducted to define the frequency, polarization, scan geometry, antenna size, and other esstential parameters of the low frequency microwave radiometer (LFMR). It will be a dual polarized, dual frequency system at 5.2 and 10.4 GHz using a 4.9 meter deployable mesh surface antenna. It is to be flown on the Navy-Remote Ocean Sensing System (N-ROSS) satellite scheduled to be launched in late 1988

A Fourier approach to cloud motion estimation

A Fourier technique is described for estimating cloud motion from pairs of pictures using the phase of the cross spectral density. The method allows motion estimates to be made for individual spatial frequencies, which are related to cloud pattern dimensions. Results obtained are presented and compared with the results of a Fourier domain cross correlation scheme. Using both artificial and real cloud data show that the technique is relatively sensitive to the presence of mixtures of motions, changes in cloud shape, and edge effects

Inference of the boundary layer structure over the oceans from satellite infrared measurements

The characteristics of the boundary layer of the atmosphere over the global oceans between about 50 deg N to 40 deg S were remotely sensed for three different periods, about 3 months each, during the year 1970. The spectral measurements made by Nimbus 4 Infrared Interferometer Spectrometer were used for this purpose

Relations between entanglement and purity in non-Markovian dynamics

Knowledge of the relationships among different features of quantumness, like entanglement and state purity, is important from both fundamental and practical viewpoints. Yet, this issue remains little explored in dynamical contexts for open quantum systems. We address this problem by studying the dynamics of entanglement and purity for two-qubit systems using paradigmatic models of radiation-matter interaction, with a qubit being isolated from the environment (spectator configuration). We show the effects of the corresponding local quantum channels on an initial two-qubit pure entangled state in the concurrence-purity diagram and find the conditions which enable dynamical closed formulas of concurrence, used to quantify entanglement, as a function of purity. We finally discuss the usefulness of these relations in assessing entanglement and purity thresholds which allow noisy quantum teleportation. Our results provide new insights about how different properties of composite open quantum systems behave and relate each other during quantum evolutions.Comment: 16 Pages, 10 Figures. One author added. Improved version with more references and comment

A phase III, multi-centre, double-masked randomised controlled trial of adjunctive intraocular and peri-ocular steroid (triamcinolone acetonide) versus standard treatment in eyes undergoing vitreoretinal surgery for open globe trauma (ASCOT): statistical analysis plan.

BACKGROUND: Open globe ocular trauma complicated by intraocular scarring (proliferative vitreoretinopathy) is a relatively rare, blinding, but potentially treatable condition for which, at present, surgery is often unsatisfactory and visual results frequently poor. To date, no pharmacological adjuncts to surgery have been proven to be effective. The aim of the Adjunctive Steroid Combination in Ocular Trauma (ASCOT) randomised controlled trial is to determine whether adjunctive steroid (triamcinolone acetonide), given at the time of surgery, can improve the outcome of vitreoretinal surgery in patients with open globe ocular trauma. This article presents the statistical analysis plan for the main publication as approved and signed off by the Trial Steering Committee prior to the first data extraction for the Data Monitoring Committee meeting report. METHODS/DESIGN: ASCOT is a pragmatic, multi-centre, parallel-group, double-masked randomised controlled trial. The aim of the study is to recruit from 20-25 centres in the United Kingdom and randomise 300 eyes (from 300 patients) into two treatment arms. Both groups will receive standard surgical treatment and care; the intervention arm will additionally receive a pre-operative steroid combination (triamcinolone acetonide) into the vitreous cavity consisting of 4 mg/0.1 ml and 40 mg/1 ml sub-Tenon's. Participants will be followed for 6 months post-surgery. The primary outcome is the proportion of patients achieving a clinically meaning improvement in visual acuity in the study eye at 6 months after initial surgery, defined as a 10 letter score improvement in the ETDRS (the standard scale to test visual acuity). TRIAL REGISTRATION: ISRCTN30012492 . Registered on 5 September 2014. EudraCT2014-002193-37 . Registered on 5 September 2014

Field-induced structure transformation in electrorheological solids

We have computed the local electric field in a body-centered tetragonal (BCT) lattice of point dipoles via the Ewald-Kornfeld formulation, in an attempt to examine the effects of a structure transformation on the local field strength. For the ground state of an electrorheological solid of hard spheres, we identified a novel structure transformation from the BCT to the face-centered cubic (FCC) lattices by changing the uniaxial lattice constant c under the hard sphere constraint. In contrast to the previous results, the local field exhibits a non-monotonic transition from BCT to FCC. As c increases from the BCT ground state, the local field initially decreases rapidly towards the isotropic value at the body-centered cubic lattice, decreases further, reaching a minimum value and increases, passing through the isotropic value again at an intermediate lattice, reaches a maximum value and finally decreases to the FCC value. An experimental realization of the structure transformation is suggested. Moreover, the change in the local field can lead to a generalized Clausius-Mossotti equation for the BCT lattices.Comment: Submitted to Phys. Rev.

Bogoliubov transformations and exact isolated solutions for simple non-adiabatic Hamiltonians

We present a new method for finding isolated exact solutions of a class of non-adiabatic Hamiltonians of relevance to quantum optics and allied areas. Central to our approach is the use of Bogoliubov transformations of the bosonic fields in the models. We demonstrate the simplicity and efficiency of this method by applying it to the Rabi Hamiltonian.Comment: LaTeX, 16 pages, 1 figure. Minor additions and journal re

On the communication cost of entanglement transformations

We study the amount of communication needed for two parties to transform some given joint pure state into another one, either exactly or with some fidelity. Specifically, we present a method to lower bound this communication cost even when the amount of entanglement does not increase. Moreover, the bound applies even if the initial state is supplemented with unlimited entanglement in the form of EPR pairs, and the communication is allowed to be quantum mechanical. We then apply the method to the determination of the communication cost of asymptotic entanglement concentration and dilution. While concentration is known to require no communication whatsoever, the best known protocol for dilution, discovered by Lo and Popescu [Phys. Rev. Lett. 83(7):1459--1462, 1999], requires a number of bits to be exchanged which is of the order of the square root of the number of EPR pairs. Here we prove a matching lower bound of the same asymptotic order, demonstrating the optimality of the Lo-Popescu protocol up to a constant factor and establishing the existence of a fundamental asymmetry between the concentration and dilution tasks. We also discuss states for which the minimal communication cost is proportional to their entanglement, such as the states recently introduced in the context of ``embezzling entanglement'' [W. van Dam and P. Hayden, quant-ph/0201041].Comment: 9 pages, 1 figure. Added a reference and some further explanations. In v3 some arguments are given in more detai

Similarity transformations approach for a generalized Fokker-Planck equation

By using similarity transformations approach, the exact propagator for a generalized one-dimensional Fokker-Planck equation, with linear drift force and space-time dependent diffusion coefficient, is obtained. The method is simple and enables us to recover and generalize special cases studied through the Lie algebraic approach and the Green function technique.Comment: 8 pages, no figure