77,481 research outputs found
Gravitational collapse: A case for thermal relaxation
Two relativistic models for collapsing spheres at different stages of
evolution, which include pre-relaxation processes, are presented. The influence
of relaxation time on the outcome of evolution in both cases is exhibited and
established. It is shown that relaxation processes can drastically change the
final state of the collapsing system. In particular, there are cases in which
the value of the relaxation time determines the bounce or the collapse of the
sphere.Comment: 33 pages, LaTex 2.09, 11 Postscript figures. To be published in
General Relativity and Gravitatio
Integrable Quasiclassical Deformations of Algebraic Curves
A general scheme for determining and studying integrable deformations of
algebraic curves is presented. The method is illustrated with the analysis of
the hyperelliptic case. An associated multi-Hamiltonian hierarchy of systems of
hydrodynamic type is characterized.Comment: 28 pages, no figure
Nonlinear Dynamics on the Plane and Integrable Hierarchies of Infinitesimal Deformations
A class of nonlinear problems on the plane, described by nonlinear
inhomogeneous -equations, is considered. It is shown that the
corresponding dynamics, generated by deformations of inhomogeneous terms
(sources) is described by Hamilton-Jacobi type equations associated with
hierarchies of dispersionless integrable systems. These hierarchies are
constructed by applying the quasiclassical -dressing method.Comment: 30 pages, tcilate
A Conversation with Dorothy Gilford
In 1946, Public Law 588 of the 79th Congress established the Office of Naval
Research (ONR). Its mission was to plan, foster and encourage scientific
research in support of Naval problems. The establishment of ONR predates the
National Science Foundation and initiated the refocusing of scientific
infrastructure in the United States following World War II. At the time, ONR
was the only source for federal support of basic research in the United States.
Dorothy Gilford was one of the first Heads of the Probability and Statistics
program at the Office of Naval Research (1955 to 1962), and she went on to
serve as Director of the Mathematical Sciences Division (1962 to 1968). During
her time at ONR, Dorothy influenced many areas of statistics and mathematics
and was ahead of her time in promoting interdisciplinary projects. Dorothy
continued her career at the National Center for Education Statistics (1969 to
1974). She was active in starting international comparisons of education
outcomes in different countries, which has influenced educational policy in the
United States. Dorothy went on to serve in many capacities at the National
Academy of Sciences, including Director of Human Resources Studies (1975 to
1978), Senior Statistician on the Committee on National Statistics (1978 to
1988) and Director of the Board on International Comparative Studies in
Education (1988 to 1994). The following is a conversation we had with Dorothy
Gilford in March of 2004. We found her to be an interesting person and a
remarkable statistician. We hope you agree.Comment: Published in at http://dx.doi.org/10.1214/088342307000000023 the
Statistical Science (http://www.imstat.org/sts/) by the Institute of
Mathematical Statistics (http://www.imstat.org
Hydrodynamic reductions and solutions of a universal hierarchy
The diagonal hydrodynamic reductions of a hierarchy of integrable
hydrodynamic chains are explicitly characterized. Their compatibility with
previously introduced reductions of differential type is analyzed and their
associated class of hodograph solutions is discussed.Comment: 19 page
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