Phonons in quantum solids with defects

A formalism was developed for temperature-dependent, self-consistent phonons in quantum solids with defects. Lattice vacancies and interstitials in solid helium and metallic hydrogen, as well as electronic excitations in solid helium, were treated as defects that modify properties of these systems. The information to be gained from the modified phonon spectrum is discussed

A critical layer model for turbulent pipe flow

A model-based description of the scaling and radial location of turbulent fluctuations in turbulent pipe flow is presented and used to illuminate the scaling behaviour of the very large scale motions. The model is derived by treating the nonlinearity in the perturbation equation (involving the Reynolds stress) as an unknown forcing, yielding a linear relationship between the velocity field response and this nonlinearity. We do not assume small perturbations. We examine propagating modes, permitting comparison of our results to experimental data, and identify the steady component of the velocity field that varies only in the wall-normal direction as the turbulent mean profile. The "optimal" forcing shape, that gives the largest velocity response, is assumed to lead to modes that will be dominant and hence observed in turbulent pipe flow. An investigation of the most amplified velocity response at a given wavenumber-frequency combination reveals critical layer-like behaviour reminiscent of the neutrally stable solutions of the Orr-Sommerfeld equation in linearly unstable flow. Two distinct regions in the flow where the influence of viscosity becomes important can be identified, namely a wall layer that scales with $R^{+1/2}$ and a critical layer, where the propagation velocity is equal to the local mean velocity, that scales with $R^{+2/3}$ in pipe flow. This framework appears to be consistent with several scaling results in wall turbulence and reveals a mechanism by which the effects of viscosity can extend well beyond the immediate vicinity of the wall.Comment: Submitted to the Journal of Fluid Mechanics and currently under revie

Information Geometry, Inference Methods and Chaotic Energy Levels Statistics

In this Letter, we propose a novel information-geometric characterization of chaotic (integrable) energy level statistics of a quantum antiferromagnetic Ising spin chain in a tilted (transverse) external magnetic field. Finally, we conjecture our results might find some potential physical applications in quantum energy level statistics.Comment: 9 pages, added correct journal referenc

Mostly Harmless: An Analysis of Post-AEDPA Federal Habeas Corpus Review of State Harmless Error Determinations

Sixty years ago, in Kotteakos v. United States, the Supreme Court ruled that a small class of so-called harmless errors committed by courts did not require correction. The Court acknowledged that some judicial errors, though recognizable as errors, did not threaten the validity of criminal convictions and therefore did not quite require reversal. Specifically, the Court held that errors that violated federal statutes should be deemed harmless unless they had a substantial and injurious effect or influence in determining the jury\u27s verdict. While Kotteakos represented the Supreme Court\u27s first treatment of the concept of harmlessness, other courts had a history of preserving convictions using harmless error review. For some time before Kotteakos, state statutes had directed appellate courts throughout the country to use harmless error review, a doctrine that prevents appellate courts from disposing of convictions on technicalities, conserve[s] judicial resources by enabling appellate courts to cleanse the judicial process of prejudicial error without becoming mired in harmless error, and allows courts to focus on decid[ing] the factual question of the defendant\u27s guilt or innocence

Two Spirits, Two Eras, Same Sex: For a Traditionalist Perspective on Native American Tribal Same-Sex Marriage Policy

Recently, several states amended their constitutions to define marriage as only a union between a man and a woman. Many Native American Indian tribal governments thereafter also adopted laws prohibiting homosexual marriages. However, this new policy conflicts with traditional tribal values. This Note shows that historically many tribes accepted and even honored same-sex unions. This Note proposes that tribes consider their traditions as they existed before European contact, and argues that, for some tribes, same-sex civil unions are a historically and culturally appropriate answer to the modern objections to same-sex marriage

Jacobi multipliers, non-local symmetries and nonlinear oscillators

Constants of motion, Lagrangians and Hamiltonians admitted by a family of relevant nonlinear oscillators are derived using a geometric formalism. The theory of the Jacobi last multiplier allows us to find Lagrangian descriptions and constants of the motion. An application of the jet bundle formulation of symmetries of differential equations is presented in the second part of the paper. After a short review of the general formalism, the particular case of non-local symmetries is studied in detail by making use of an extended formalism. The theory is related to some results previously obtained by Krasil'shchi, Vinogradov and coworkers. Finally the existence of non-local symmetries for such two nonlinear oscillators is proved.Comment: 20 page

The Adsorption of Atomic Nitrogen on Ru(0001): Geometry and Energetics

The local adsorption geometries of the (2x2)-N and the (sqrt(3)x sqrt(3))R30^o -N phases on the Ru(0001) surface are determined by analyzing low-energy electron diffraction (LEED) intensity data. For both phases, nitrogen occupies the threefold hcp site. The nitrogen sinks deeply into the top Ru layer resulting in a N-Ru interlayer distance of 1.05 AA and 1.10 AA in the (2x2) and the (sqrt(3)x sqrt(3))R30^o unit cell, respectively. This result is attributed to a strong N binding to the Ru surface (Ru--N bond length = 1.93 AA) in both phases as also evidenced by ab-initio calculations which revealed binding energies of 5.82 eV and 5.59 eV, respectively.Comment: 17 pages, 5 figures. Submitted to Chem. Phys. Lett. (October 10, 1996

Environmental Response Management Application

The Coastal Response Research Center (CRRC), a partnership between the University of New Hampshire (UNH) and NOAA\u27s Office of Response and Restoration (ORR), is leading an effort to develop a data platform capable of interfacing both static and real-time data sets accessible simultaneously to a command post and assets in the field with an open source internet mapping server. The Environmental Response Management Application (ERMA™) is designed to give responders and decision makers ready access to geographically specific data useful during spill planning/drills, incident response, damage assessment and site restoration. In addition to oil spill and chemical release response, this website can be relevant to other environmental incidents and natural disasters, responses and regional planning efforts. The platform is easy to operate, without the assistance of Information Technology or Geographic Information Systems (GIS) specialists. It allows users to access individual data layer values, overlay relevant data sets, and zoom into segments of interest. The platform prototype is being developed specifically for Portsmouth Harbor and the Great Bay Estuary, NH. The prototype demonstrates the capabilities of an integrated data management platform and serves as the pilot for web-based GIS platforms in other regions

On the basic mechanism of Pixelized Photon Detectors

A Pixelized Photon Detector (PPD) is a generic name for the semiconductor devices operated in the Geiger-mode, such as Silicon PhotoMultiplier and Multi-Pixel Photon Counter, which has high photon counting capability. While the internal mechanisms of the PPD have been intensively studied in recent years, the existing models do not include the avalanche process. We have simulated the multiplication and quenching of the avalanche process and have succeeded in reproducing the output waveform of the PPD. Furthermore our model predicts the existence of dead-time in the PPD which has never been numerically predicted. For serching the dead-time, we also have developed waveform analysis method using deconvolution which has the potential to distinguish neibouring pulses precisely. In this paper, we discuss our improved model and waveform analysis method.Comment: 4pages, 5figures, To appear in the proceedings of 5th International Conference on New Developments in Photodetection (NDIP08), Aix-les-Bains, France, 15-20 Jun 200

Labour Standards in the Ghanaian Construction Sector: an investigation of the governance landscape

Purpose This paper aims to investigate the governance of labour standards in the less-studied yet rapidly globalising Ghanaian construction sector. While incorporation into international production networks generates several opportunities for workers, the drivers of adverse incorporation originate at multiple levels of analysis. The study offers an investigation into such drivers and their interconnections. Design/methodology/approach The authors utilise a multi-scalar framework and mixed methods of analysis. Both the qualitative and multi-level quantitative analyses rely on a primary dataset collected among 30 firms and 304 respondents, through semi-structured interviews. Findings A composite yet unbalanced labour standards governance configuration emerges, where the absence of social governance combined with a weak role of the State leaves labour standards subject to the variegated landscape of firms' embeddedness in the sector. Originality/value The construction industry is acquiring ever-increasing relevance in the economic trajectory of Ghana as well as that of several other African economies, not least for its large employment generation potential. Research on the governance of labour standards in the sector is, however, largely missing. The authors argue that labour incorporation dynamics represent a complex under-investigated regulatory challenge as well as a policy-making priority. The analysis is one of the first to offer a reconstruction of the governance landscape determining the challenges workers face in the Ghanaian construction sector, from both a qualitative and quantitative perspective