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Full-Text Articles in Physical Sciences and Mathematics

The Spinor Representation Of Minimal Surfaces, Rob Kusner, Nick Schmitt Dec 1995

The Spinor Representation Of Minimal Surfaces, Rob Kusner, Nick Schmitt

Mathematics and Statistics Department Faculty Publication Series

The spinor representation is developed and used to investigate minimal surfaces in R^3 with embedded planar ends. The moduli spaces of planar-ended minimal spheres and real projective planes are determined, and new families of minimal tori and Klein bottles are given. These surfaces compactify in S^3 to yield surfaces critical for the M¨obius invariant squared mean curvature functional W. On the other hand, all Wcritical spheres and real projective planes arise this way. Thus we determine at the same time the moduli spaces of W-critical spheres and real projective planes via the spinor representation.


Croatian Symposium Of Chemistry And Macromolecular Chemistry, Otto Vogl, Zvonimir Janovic Dec 1995

Croatian Symposium Of Chemistry And Macromolecular Chemistry, Otto Vogl, Zvonimir Janovic

Emeritus Faculty Author Gallery

No abstract provided.


Polymer Science In Australia Iv. Universities In Victoria And Southern Australia, Otto Vogl, David Solomon, Ezio Rizzardo, Robert A. Shanks, David Williams Dec 1995

Polymer Science In Australia Iv. Universities In Victoria And Southern Australia, Otto Vogl, David Solomon, Ezio Rizzardo, Robert A. Shanks, David Williams

Emeritus Faculty Author Gallery

No abstract provided.


52. Bengt Ranby, Otto Vogl Dec 1995

52. Bengt Ranby, Otto Vogl

Emeritus Faculty Author Gallery

No abstract provided.


53. Takeo Saegusa, Otto Vogl Nov 1995

53. Takeo Saegusa, Otto Vogl

Emeritus Faculty Author Gallery

No abstract provided.


54. Burkart Philipp, Otto Vogl, Ch. Wandrey Oct 1995

54. Burkart Philipp, Otto Vogl, Ch. Wandrey

Emeritus Faculty Author Gallery

No abstract provided.


55. Hermann Janeschitz-Kriegl, Otto Vogl, Anton Schausberger Sep 1995

55. Hermann Janeschitz-Kriegl, Otto Vogl, Anton Schausberger

Emeritus Faculty Author Gallery

No abstract provided.


56. Sir Geoffrey Allan, Otto Vogl, Shigeko Suzuki Aug 1995

56. Sir Geoffrey Allan, Otto Vogl, Shigeko Suzuki

Emeritus Faculty Author Gallery

No abstract provided.


57. Peter Plesch, Otto Vogl, Traudl Plesch Jul 1995

57. Peter Plesch, Otto Vogl, Traudl Plesch

Emeritus Faculty Author Gallery

No abstract provided.


58. Koichi Hatada, Otto Vogl, Michiko Hatada Jun 1995

58. Koichi Hatada, Otto Vogl, Michiko Hatada

Emeritus Faculty Author Gallery

No abstract provided.


59. Otto Kratky, 1902-1995, Otto Vogl, Josef Schurz May 1995

59. Otto Kratky, 1902-1995, Otto Vogl, Josef Schurz

Emeritus Faculty Author Gallery

No abstract provided.


60. Teiji Tsuruta, Otto Vogl Apr 1995

60. Teiji Tsuruta, Otto Vogl

Emeritus Faculty Author Gallery

No abstract provided.


61. Marian Kryszewski, Otto Vogl Mar 1995

61. Marian Kryszewski, Otto Vogl

Emeritus Faculty Author Gallery

No abstract provided.


62. David M Solomon, Otto Vogl, Kenneth Ghiggino Feb 1995

62. David M Solomon, Otto Vogl, Kenneth Ghiggino

Emeritus Faculty Author Gallery

No abstract provided.


63. Ivan Panayotov, Otto Vogl, Christo Tsvetanov Jan 1995

63. Ivan Panayotov, Otto Vogl, Christo Tsvetanov

Emeritus Faculty Author Gallery

No abstract provided.


Performance Evaluation Of An Axially Viewed Horizontal Inductively-Coupled Plasma For Optical-Emission Spectrometry, Jc Ivaldi, Jf Tyson Jan 1995

Performance Evaluation Of An Axially Viewed Horizontal Inductively-Coupled Plasma For Optical-Emission Spectrometry, Jc Ivaldi, Jf Tyson

Chemistry Department Faculty Publication Series

No abstract provided.


Determination Of Formation Quotients By A Flow-Injection Procedure, Rt Echols, Jf Tyson Jan 1995

Determination Of Formation Quotients By A Flow-Injection Procedure, Rt Echols, Jf Tyson

Chemistry Department Faculty Publication Series

No abstract provided.


The Use Of Nafion Dryer Tubes For Moisture Removal In Flow Injection Chemical Vapor Generation Atomic Absorption Spectrometry, Ng Sundin, Julian Tyson, C P. Hanna, S A. Mcintosh Jan 1995

The Use Of Nafion Dryer Tubes For Moisture Removal In Flow Injection Chemical Vapor Generation Atomic Absorption Spectrometry, Ng Sundin, Julian Tyson, C P. Hanna, S A. Mcintosh

Chemistry Department Faculty Publication Series

A significant problem with flow injection chemical vapor generation atomic absorption spectrometry is a loss of sensitivity and blockage of transfer lines due to excessive moisture transported to the atom cell or lodged in the transfer line. A Nafion dryer tube was used to remove moisture from the wet carrier gas stream. The hygroscopic Nafion membrane removed water at 1.7 mg/min at an efficiency of 95 ± 4% when SnCl2 was used as the reductant. When 0.4% (m/v) borohydride was used as the reductant, 2.3 mg/min of water was removed at an efficiency of 91 ± 3%. No measurable change …


Dressing Orbits Of Harmonic Maps, Fe Burstall, F Pedit Jan 1995

Dressing Orbits Of Harmonic Maps, Fe Burstall, F Pedit

Mathematics and Statistics Department Faculty Publication Series

We study the harmonic map equations for maps of a Riemann surface into a Riemannian symmetric space of compact type from the point of view of soliton theory. There is a well-known dressing action of a loop group on the space of harmonic maps and we discuss the orbits of this action through particularly simple harmonic maps called {\em vacuum solutions}. We show that all harmonic maps of semisimple finite type (and so most harmonic $2$-tori) lie in such an orbit. Moreover, on each such orbit, we define an infinite-dimensional hierarchy of commuting flows and characterise the harmonic maps of …


2-Loop Analysis Of Vector-Current Propagators In Chiral Perturbation-Theory, E Golowich, J Kambor Jan 1995

2-Loop Analysis Of Vector-Current Propagators In Chiral Perturbation-Theory, E Golowich, J Kambor

Physics Department Faculty Publication Series

We perform a calculation of the isospin and hypercharge vector-current propagators (ΔV33μν(q2) and ΔV88μν(q2)) to two loops in chiral perturbation theory. The analysis is carried out with straight-forward Feynman diagram methods by making appropriate use of external vector sources. Counterterms from the (q6) chiral lagrangian, required to absorb divergences and scale dependence encountered at the two-loop level, are constructed. Our final results are finite, covariant, and scale-independent. Several applications are described, including a comparison of the two-loop isospin vector spectral function with data and the construction of new chiral sum rules.


Chiral Perturbation Theory: A Primer, Br Holstein Jan 1995

Chiral Perturbation Theory: A Primer, Br Holstein

Physics Department Faculty Publication Series

Recently methods have been developed which exploit the chiral symmetry of QCD in order to make rigorous contact with low energy particle physics phenomenology. In these lectures we present a pedagogical introduction to these techniques.


A Status Report On Chiral Dynamics: Theory And Experiment, Aron M. Benstein, Barry Holstein Jan 1995

A Status Report On Chiral Dynamics: Theory And Experiment, Aron M. Benstein, Barry Holstein

Physics Department Faculty Publication Series

This paper gives an overview of a Workshop on Chiral Dynamics: Theory and Experiment which was held at MIT July 25-29, 1994; its unique feature was the equal mixture of theory and experiment. The purpose of the workshop was to bring together many of the active participants to assess the status of the field and to explore fruitful future directions. The foundations and present status of the theory were reviewed as well as the experimental status of the field. To facilitate the discussion of future directions working groups were organized on Threshold Photo/Electropion Production, Two-Pion Threshold and the Chiral Anomaly, …


Breaking Cosmic Strings Without Monopoles, D Eardley, G Horowitz, David Kastor, Jennie Traschen Jan 1995

Breaking Cosmic Strings Without Monopoles, D Eardley, G Horowitz, David Kastor, Jennie Traschen

Physics Department Faculty Publication Series

It is shown that topologically stable cosmic strings can, in fact, appear to end or to break, even in theories without monopoles. This can occur whenever the spatial topology of the universe is nontrivial. For the case of Abelian-Higgs strings, we describe the gauge and scalar field configurations necessary for a string to end on a black hole. We give a lower bound for the rate at which a cosmic string will break via black hole pair production, using an instanton calculation based on the Euclidean C-metric.


Calculation Of A Weak Nonleptonic Matrix Element Using “Weinberg” Sum Rules, John Donoghue Jan 1995

Calculation Of A Weak Nonleptonic Matrix Element Using “Weinberg” Sum Rules, John Donoghue

Physics Department Faculty Publication Series

There is a ``toy'' weak matrix element which can be expressed as an integral over the vector and axial vector spectral functions, $\rho_V (s) - \rho_A (s)$. I review our recent evaluation of these spectral functions, the study of four ``Weinberg'' sum rules and the calculation of this matrix element.


Nn, N-Delta Couplings And The Quark-Model, Tr Hemmert, Br Holstein, Nc Mukhopadhyay Jan 1995

Nn, N-Delta Couplings And The Quark-Model, Tr Hemmert, Br Holstein, Nc Mukhopadhyay

Physics Department Faculty Publication Series

We examine mass-corrected SU(6) symmetry predictions in the quark model relating vector, axial-vector, and strong NN and NΔ couplings, and demonstrate that the experimental NΔ value is significantly higher than predicted in each case. Nevertheless the Goldberger-Treiman relation is satisfied in both sectors. Possible origins of the discrepancy of the quark model predictions with experiments are discussed.


Production Of Milky-Way Structure By The Magellanic-Clouds, Md Weinberg Jan 1995

Production Of Milky-Way Structure By The Magellanic-Clouds, Md Weinberg

Astronomy Department Faculty Publication Series

Previous attempts at disturbing the galactic disk by the Magellanic Clouds relied on direct tidal forcing. However, by allowing the halo to actively respond rather than remain a rigid contributor to the rotation curve, the Clouds may produce a wake in the halo which then distorts the disk. Recent work reported here suggests that the Magellanic Clouds use this mechanism to produce disk distortions sufficient to allow for both the radial location, position angle and sign of the HI warp and observed anomalies in stellar kinematics toward the galactic anticenter and LSR motion.


Lightweight Write Detection And Checkpointing For Fine-Grained Persistence, Antony L. Hosking, J. Eliot B. Moss Jan 1995

Lightweight Write Detection And Checkpointing For Fine-Grained Persistence, Antony L. Hosking, J. Eliot B. Moss

Computer Science Department Faculty Publication Series

Many systems must dynamically track writes to cached data, for the purpose of reconciling those updates with respect to the permanent or global state of the data. For example, distributed systems employ coherency protocols to ensure a consistent view of shared data. Similarly, database systems log updates both for concurrency control and to ensure the resilience of those updates in the face of system failures. Here, we measure and compare the absolute performance of several alternative mechanisms for the lightweight detection of writes to cached data in a persistent system, and the relative overhead to log those writes to stable …


Large Deviations And The Generalized Processor Sharing Scheduling: Upper And Lower Bounds Part I: Two-Queue Systems, Zhi-Li Zhang Jan 1995

Large Deviations And The Generalized Processor Sharing Scheduling: Upper And Lower Bounds Part I: Two-Queue Systems, Zhi-Li Zhang

Computer Science Department Faculty Publication Series

We prove asymptotic upper and lower bounds on the asymptotic decay rate of per-session queue length tail distributions for a single constant service rate server queue shared by multiple sessions with the generalized processor sharing (GPS) scheduling discipline. The simpler case of a GPS system with only two queues needs special attention, as under this case, it is shown that the upper bounds and lower boundsmatch, thus yielding exact bounds. This result is established in this part (Part I) of the paper. The general case is much more complicated, and is treated separately in Part II of the paper [42], …


Coordination Assistance For Mixed Human And Computational Agent Systems, Keith S. Decker, Victor R. Lesser Jan 1995

Coordination Assistance For Mixed Human And Computational Agent Systems, Keith S. Decker, Victor R. Lesser

Computer Science Department Faculty Publication Series

In many application areas (such as concurrent engineering, software development, hospital scheduling, manufacturing scheduling, and military planning), individuals are responsible for an agenda of tasks and face choices about the best way to locally handle each task, in what order to do tasks, and when to do them. Such decisions are often hard tomake because of coordination problems: individual tasks are related to the tasks of others in complex ways, and there aremany sources of uncertainty (no one has a complete view of the task structure at arbitrary levels of detail, the situationmay be changing dynamically, and no one is …


Crystal: Inducing A Conceptual Dictionary, Stephen Soderland Jan 1995

Crystal: Inducing A Conceptual Dictionary, Stephen Soderland

Computer Science Department Faculty Publication Series

One of the central knowledge sources of an information extraction (IE) system IS a dictionary of linguistic patterns that can be used to identify references to relevant information in a text Automatic creation of conceptual dictionaries is important for portability and scalability of an IE system This paper describes CRYSTAL, a system which automatically induces a dictionary of "concept-node definitions" sufficient to identify relevant information from a training corpus Each of these concept-node definitions is generalized as far as possible without producing errors, so that a minimum number of dictionary entries cover the positive training instances Because it tests the …