Vortices, Instantons and Branes

The purpose of this paper is to describe a relationship between the moduli space of vortices and the moduli space of instantons. We study charge k vortices in U(N) Yang-Mills-Higgs theories and show that the moduli space is isomorphic to a special Lagrangian submanifold of the moduli space of k instantons in non-commutative U(N) Yang-Mills theories. This submanifold is the fixed point set of a U(1) action on the instanton moduli space which rotates the instantons in a plane. To derive this relationship, we present a D-brane construction in which the dynamics of vortices is described by the Higgs branch of a U(k) gauge theory with 4 supercharges which is a truncation of the familiar ADHM gauge theory. We further describe a moduli space construction for semi-local vortices, lumps in the CP(N) and Grassmannian sigma-models, and vortices on the non-commutative plane. We argue that this relationship between vortices and instantons underlies many of the quantitative similarities shared by quantum field theories in two and four dimensions.Comment: 32 Pages, 4 Figure

Milankovitch-paced erosion in the southern Central Andes

It has long been hypothesized that climate can modify both the pattern and magnitude of erosion in mountainous landscapes, thereby controlling morphology, rates of deformation, and potentially modulating global carbon and nutrient cycles through weathering feedbacks. Although conceptually appealing, geologic evidence for a direct climatic control on erosion has remained ambiguous owing to a lack of high-resolution, long-term terrestrial records and suitable field sites. Here we provide direct terrestrial field evidence for long-term synchrony between erosion rates and Milankovitch-driven, 400-kyr eccentricity cycles using a Plio-Pleistocene cosmogenic radionuclide paleo-erosion rate record from the southern Central Andes. The observed climate-erosion coupling across multiple orbital cycles, when combined with results from the intermediate complexity climate model CLIMBER-2, are consistent with the hypothesis that relatively modest fluctuations in precipitation can cause synchronous and nonlinear responses in erosion rates as landscapes adjust to ever-evolving hydrologic boundary conditions imposed by oscillating climate regimes

Computational and Mathematical Organization Theory Affiliation of Authors

January 2004: Special Issue on Mathematical representations for the analysis of social networks within and between organization

Lesser and Canadian sandhill crane populations, age structure, and harvest /

Includes bibliographies.Mode of access: Internet

FORMAT : Fortran matrix abstraction technique.

The FORMAT System has been augmented with highly efficient and reliable procedures for structural analysis via an alternate solution approach which combines the rigorous generation features of the existing force method with a few new equation solving process characteristic of the current displacement methods. As a result, a tenfold increase in potential problem size to in excess of 10000 elastic degrees of freedom is the minimum currently anticipated as attainable on present major digital computers, and the linear behavioral characteristics can take immediate advantage of any advance in hardware capabilities. In making these provisions considerable emphasis was placed on the control of both physical and numerical error throughout the total solution process. To actual aerospace structures with up to 6500 degrees of freedom have been successfully processed as single entities on a production basis, that is, within the confines of a production schedule with maximum reliability at minimum cost.Research supported by the Air Force Flight Dynamics Laboratory, Air Force Systems Command, United States Air Force, and performed by the Douglas Aircraft Company."April 1973."Includes bibliographical references (pages 131-132).The FORMAT System has been augmented with highly efficient and reliable procedures for structural analysis via an alternate solution approach which combines the rigorous generation features of the existing force method with a few new equation solving process characteristic of the current displacement methods. As a result, a tenfold increase in potential problem size to in excess of 10000 elastic degrees of freedom is the minimum currently anticipated as attainable on present major digital computers, and the linear behavioral characteristics can take immediate advantage of any advance in hardware capabilities. In making these provisions considerable emphasis was placed on the control of both physical and numerical error throughout the total solution process. To actual aerospace structures with up to 6500 degrees of freedom have been successfully processed as single entities on a production basis, that is, within the confines of a production schedule with maximum reliability at minimum cost.Air Force Contract No.Mode of access: Internet

FORMAT : Fortran matrix abstraction technique.

FORMAT (Fortran Matrix Abstraction Technique) is a digital computer program system consisting of three distinct programs written entirely in Fortran IV. The system provides for generation, manipulating, printing, and plotting of large order (i.e., 2000) matrices commonly used in state-of-the-art structural analyses. Phase I of the system automatically generates matrices required in the thermomechanical analysis of structures by the Force or Displacement Methods including those necessary in joining, symmetric/antisymmetric r reaction disconnect, vibration, and stability analyses. Modules for converting continuous-to-discrete loads, and analytic-to-discrete geometry and for maintenance of a master case data file are also provided to minimize input data requirements. Phase II provides an abstraction capability to effect basic matrix algebra via the standard matrix operations (e.g., add, multiply, etc.), and several control operations (e.g., save and print matrices, etc.). The sequence of operations is user designated. Phase III provides for self-explanatory report form printing of matrix data resulting from Force or Displacement Method analyses, and a nominal graphical display capability for matrix and geometry data."Research supported by the Air Force Flight Dynamics Laboratory, Research and Technology Division, Air Force Systems Command, United States Air Force, and performed by the Douglas Aircraft Company, Aircraft Division."AD0683261 (from http://www.dtic.mil)."December 1968."Includes bibliographical references (pages 687-688).FORMAT (Fortran Matrix Abstraction Technique) is a digital computer program system consisting of three distinct programs written entirely in Fortran IV. The system provides for generation, manipulating, printing, and plotting of large order (i.e., 2000) matrices commonly used in state-of-the-art structural analyses. Phase I of the system automatically generates matrices required in the thermomechanical analysis of structures by the Force or Displacement Methods including those necessary in joining, symmetric/antisymmetric r reaction disconnect, vibration, and stability analyses. Modules for converting continuous-to-discrete loads, and analytic-to-discrete geometry and for maintenance of a master case data file are also provided to minimize input data requirements. Phase II provides an abstraction capability to effect basic matrix algebra via the standard matrix operations (e.g., add, multiply, etc.), and several control operations (e.g., save and print matrices, etc.). The sequence of operations is user designated. Phase III provides for self-explanatory report form printing of matrix data resulting from Force or Displacement Method analyses, and a nominal graphical display capability for matrix and geometry data.Air Force Contract No.Mode of access: Internet