Variational approach in weighted Sobolev spaces to scattering by unbounded rough surfaces

We consider the problem of scattering of time harmonic acoustic waves by an unbounded sound soft surface which is assumed to lie within a finite distance of some plane. The paper is concerned with the study of an equivalent variational formulation of this problem set in a scale of weighted Sobolev spaces. We prove well-posedness of this variational formulation in an energy space with weights which extends previous results in the unweighted setting [S. Chandler-Wilde and P. Monk, SIAM J. Math. Anal., 37 (2005), pp. 598–618] to more general inhomogeneous terms in the Helmholtz equation. In particular, in the two-dimensional case, our approach covers the problem of plane wave incidence, whereas in the three-dimensional case, incident spherical and cylindrical waves can be treated. As a further application of our results, we analyze a finite section type approximation, whereby the variational problem posed on an infinite layer is approximated by a variational problem on a bounded region

Study of EVA operations associated with satellite services

Extravehicular mobility unit (EMU) factors associated with satellite servicing activities are identified and the EMU improvements necessary to enhance satellite servicing operations are outlined. Areas of EMU capabilities, equipment and structural interfaces, time lines, EMU modifications for satellite servicing, environmental hazards, and crew training are vital to manned Eva/satellite services and as such are detailed. Evaluation of EMU capabilities indicates that the EMU can be used in performing near term, basic satellite servicing tasks; however, satellite servicing is greatly enhanced by incorporating key modifications into the EMU. The servicing missions involved in contamination sensitive payload repair are illustrated. EVA procedures and equipment can be standardized, reducing both crew training time and in orbit operations time. By standardizing and coordinating procedures, mission cumulative time lines fall well within the EMU capability

Convergence analysis of a multigrid algorithm for the acoustic single layer equation

We present and analyze a multigrid algorithm for the acoustic single layer equation in two dimensions. The boundary element formulation of the equation is based on piecewise constant test functions and we make use of a weak inner product in the multigrid scheme as proposed in \cite{BLP94}. A full error analysis of the algorithm is presented. We also conduct a numerical study of the effect of the weak inner product on the oscillatory behavior of the eigenfunctions for the Laplace single layer operator

Stochastic resonance in Gaussian quantum channels

We determine conditions for the presence of stochastic resonance in a lossy bosonic channel with a nonlinear, threshold decoding. The stochastic resonance effect occurs if and only if the detection threshold is outside of a "forbidden interval". We show that it takes place in different settings: when transmitting classical messages through a lossy bosonic channel, when transmitting over an entanglement-assisted lossy bosonic channel, and when discriminating channels with different loss parameters. Moreover, we consider a setting in which stochastic resonance occurs in the transmission of a qubit over a lossy bosonic channel with a particular encoding and decoding. In all cases, we assume the addition of Gaussian noise to the signal and show that it does not matter who, between sender and receiver, introduces such a noise. Remarkably, different results are obtained when considering a setting for private communication. In this case the symmetry between sender and receiver is broken and the "forbidden interval" may vanish, leading to the occurrence of stochastic resonance effects for any value of the detection threshold.Comment: 17 pages, 6 figures. Manuscript improved in many ways. New results on private communication adde

Study of contamination of liquid oxygen by gaseous nitrogen First quarterly report, 1 Jul. - 30 Sep. 1964

Analytical model development for contamination study of liquid oxygen by gaseous nitroge

Noise and disturbance in quantum measurements: an information-theoretic approach

We introduce information-theoretic definitions for noise and disturbance in quantum measurements and prove a state-independent noise-disturbance tradeoff relation that these quantities have to satisfy in any conceivable setup. Contrary to previous approaches, the information-theoretic quantities we define are invariant under relabelling of outcomes, and allow for the possibility of using quantum or classical operations to `correct' for the disturbance. We also show how our bound implies strong tradeoff relations for mean square deviations.Comment: v3: to appear on PRL (some issues fixed, supplemental material expanded). v2: replaced with submitted version; 5 two-column pages + 6 one-column pages + 3 figures; one issue corrected and few references added. v1: 17 pages, 3 figure

American Bishops and Religious Freedom: Legacy and Limits

This paper explores continuity and change in the American Catholic hierarchy’s promotion of and later reliance on religious freedom. With an analysis spanning more than 50 years, it first traces the pressures for reform that created the Declaration more than 50 years ago, demonstrating that American bishops were crucial actors in the Declaration’s existence and passage, and that this was the case because of the strong legitimacy pressures they were under as Roman Catholic leaders in a predominantly Protestant country. The paper then turns to a summary of how the Birth Control Mandate of the Affordable Care Act once again created pressures for legitimacy for the American Catholic hierarchy, pressures which were again articulated in terms of critiques of hypocrisy. It demonstrates that although the specific critique changed, accusations of hypocrisy remain central in discussions of the Catholic Church’s stance on the Birth Control Mandate in the Affordable Care Act

Readiness for kindergarten reading readiness work books

Thesis (Ed.M.)--Boston Universit

Editorial: Complex Religion: Intersections of Religion and Inequality

What is complex religion and how does it relate to social inclusion? Complex religion is a theory which posits that religion intersects with inequality, especially class, race, ethnicity and gender. The nine articles in this volume examine a wide array of ways that religion intersects with inequality, and how, as a result, it can create barriers to social inclusion. The issue begins with three articles that examine the role of religion and its intersection with race and racialization processes. It then moves to three articles that examine religion’s intersection with socioeconomic inequality. The issue closes with three studies of how religion’s relationship with the state creates and maintains various status hierarchies, even as some religious movements seek to combat inequality. Together, these articles enrichen our understanding of the complex task before anyone seeking to think about the role of religion in social inclusion