Quantum collision theory with phase-space distributions

Quantum-mechanical phase-space distributions, introduced by Wigner in 1932, provide an intuitive alternative to the usual wave-function approach to problems in scattering and reaction theory. The aim of the present work is to collect and extend previous efforts in a unified way, emphasizing the parallels among problems in ordinary quantum theory, nuclear physics, chemical physics, and quantum field theory. The method is especially useful in providing easy reductions to classical physics and kinetic regimes under suitable conditions. Section II, dealing in detail with potential scattering of a spinless nonrelativistic particle, provides the background for more complex problems. Following a brief description of the two-body problem, the authors address the N-body problem with special attention to hierarchy closures, Boltzmann-Vlasov equations, and hydrodynamic aspects. The final section sketches past and possibly future applications to a wide variety of problems

Dynamics of secondary succession in a grassland ecosystem

Ph.D.Willard R. Fe

Renewal of a linear electrical network simulator into Ada

A dissertation submitted to the Faculty of Engineering, University of the Witwatersrand, Johannesburg, in fulfilment Of the requirements for the degree of Master of Science in Engineering. Johannesburg, 1993Renewal is the extraction of the intellectual content (algorithms, data structures) from an existing program, and then puilding a new more maiatainable program using more modem progra1Tlming methods and languages. A survey of software structure on maintenance. highlighted the different hierarchies produced by functional and object-oriented design methods. Elecsim, a linear circuit sL~ulator written in Pascal, was chosen as the existing program to be renewed, The new version follows the approach of decoupling the user interface and introducing an explicit scheduler. The object-oriented design technique is used extensively. Other issues addressed include online-help and. documentation for the program. Conclusions are drawn which are generally applicable from the specificlessons learnt from the Elecsim/Elector case study.MT201

Multi-Omics for the Understanding of Brain Diseases

Omics technologies such as proteomics, genomics, and metabolomics are widely applied for the identification and characterization of new molecular signatures. However, molecular profiling that makes it possible to understand neurodegenerative diseases has been relatively insufficient. Brain diseases such as neurodegenerative diseases and emotional disorders need integrative understanding which draws on a more reliable hypothesis for pathology, which can be accomplished via in-depth study of molecular information. Recently, multi-omics technologies have been eagerly applied to a diverse range of diseases. As this includes multiple molecular profiling, metadata, and Big Data processing with informatics and computer science, it is possible to provide new macroscopic and microscopic insights in order to better understand diseases. This Special Issue will introduce recent technological advances in multi-omics and the application of omics technology to brain diseases

Information transfer in complex systems, with applications to regulation Interim scientific report

Information theory and relevance to study of complex system

Research reports: 1990 NASA/ASEE Summer Faculty Fellowship Program

Reports on the research projects performed under the NASA/ASEE Summer Faculty Fellowship Program are presented. The program was conducted by The University of Alabama and MSFC during the period from June 4, 1990 through August 10, 1990. Some of the topics covered include: (1) Space Shuttles; (2) Space Station Freedom; (3) information systems; (4) materials and processes; (4) Space Shuttle main engine; (5) aerospace sciences; (6) mathematical models; (7) mission operations; (8) systems analysis and integration; (9) systems control; (10) structures and dynamics; (11) aerospace safety; and (12) remote sensin

Early Urbanism in the Northern Fertile Crescent: A Comparison of Regional Settlement Trajectories and Millennial Landscape Change

This thesis investigates the development of urban centres in the Northern Fertile Crescent during the Late Chalcolithic and Early Bronze Age and seeks to place this development in a wider context of landscape transformation over time. Settlement data from eight archaeological surveys covering a range of landscape types and environments are brought into a single interpretive framework, organised through a Geographical Information System (GIS). These surveys are enhanced through the use of satellite imagery, particularly Corona spy photography, to discover new sites both within and outside the boundaries of their original areas. Methods for the incorporation of this wide range of data are developed, including the use of concepts such as ‘certainty’ and ‘precision’ and techniques for the comparison of multiple chronological systems. These new methods are used to undertake a multi-scalar examination of settlement trajectories from the 5th to the 3rd millennium. Two phases of urban development are evident, first in the Late Chalcolithic and then during the ‘second urban revolution’ (Akkermans and Schwartz 2003) in the later Early Bronze Age. Whilst the Late Chalcolithic centres emerged within dense landscapes of small settlements, urbanisation in the later Early Bronze Age was accompanied by the widespread incursion of settlement into a ‘zone of uncertainty’ on the margins of the steppe. It is argued that a combination of factors, including the shift from flax to wool as the raw material in textile production and the development of social institutions capable of bearing risks at a large scale, provided the incentive and the means for this expansion, and that this transformed the societies of the region as a whole. This phenomenon is then placed in the wider context of long-term landscape change. It is argued that differences in settlement histories across the region can account for variations in the preservation of the archaeological record

Research in Structures, Structural Dynamics and Materials, 1990

The Structural Dynamics and Materials (SDM) Conference was held on April 2 to 4, 1990 in Long Beach, California. This publication is a compilation of presentations of the work-in-progress sessions and does not contain papers from the regular sessions since those papers are published by AIAA in the conference proceedings

Astrophysical Searches and Constraints on Ultralight Bosonic Dark Matter

Starting from the evidence that dark matter indeed exists and permeates the entire cosmos, various bounds on its properties can be estimated. Beginning with the cosmic microwave background and large scale structure, we summarize bounds on the ultralight bosonic dark matter (UBDM) mass and cosmic density. These bounds are extended to larger masses by considering galaxy formation and evolution, and the phenomenon of black hole superradiance. We then discuss the formation of different classes of UBDM compact objects including solitons/axion stars and miniclusters. Next, we consider astrophysical constraints on the couplings of UBDM to Standard Model particles, from stellar cooling (production of UBDM) and indirect searches (decays or conversion of UBDM). Throughout, there are short discussions of "hints and opportunities" in searching for UBDM in each area.Comment: 46 pages, 8 figures. To appear as Chapter 3 in "The Search for Ultralight Bosonic Dark Matter," edited by Derek F. Jackson Kimball & Karl van Bibber (Springer, 2021). Solutions for the problems are include