96 research outputs found
Asymptotic conservation laws in field theory
A new, general, field theoretic approach to the derivation of asymptotic
conservation laws is presented. In this approach asymptotic conservation laws
are constructed directly from the field equations according to a universal
prescription which does not rely upon the existence of Noether identities or
any Lagrangian or Hamiltonian formalisms. The resulting general expressions of
the conservation laws enjoy important invariance properties and synthesize all
known asymptotic conservation laws, such as the ADM energy in general
relativity.Comment: 13 pages, AMS-TeX, amsppt.sty, revised to give a better exposition
(we hope), and to correct some typesetting error
Cohomologies of the Poisson superalgebra
Cohomology spaces of the Poisson superalgebra realized on smooth
Grassmann-valued functions with compact support on ($C^{2n}) are
investigated under suitable continuity restrictions on cochains. The first and
second cohomology spaces in the trivial representation and the zeroth and first
cohomology spaces in the adjoint representation of the Poisson superalgebra are
found for the case of a constant nondegenerate Poisson superbracket for
arbitrary n>0. The third cohomology space in the trivial representation and the
second cohomology space in the adjoint representation of this superalgebra are
found for arbitrary n>1.Comment: Comments: 40 pages, the text to appear in Theor. Math. Phys.
supplemented by computation of the 3-rd trivial cohomolog
Morita base change in Hopf-cyclic (co)homology
In this paper, we establish the invariance of cyclic (co)homology of left
Hopf algebroids under the change of Morita equivalent base algebras. The
classical result on Morita invariance for cyclic homology of associative
algebras appears as a special example of this theory. In our main application
we consider the Morita equivalence between the algebra of complex-valued smooth
functions on the classical 2-torus and the coordinate algebra of the
noncommutative 2-torus with rational parameter. We then construct a Morita base
change left Hopf algebroid over this noncommutative 2-torus and show that its
cyclic (co)homology can be computed by means of the homology of the Lie
algebroid of vector fields on the classical 2-torus.Comment: Final version to appear in Lett. Math. Phy
Modeling a Two-Stage High-Power Anode Layer Thruster and its Plume
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76625/1/AIAA-22185-240.pd
Equivalence of conservation laws and equivalence of potential systems
We study conservation laws and potential symmetries of (systems of)
differential equations applying equivalence relations generated by point
transformations between the equations. A Fokker-Planck equation and the Burgers
equation are considered as examples. Using reducibility of them to the
one-dimensional linear heat equation, we construct complete hierarchies of
local and potential conservation laws for them and describe, in some sense, all
their potential symmetries. Known results on the subject are interpreted in the
proposed framework. This paper is an extended comment on the paper of J.-q. Mei
and H.-q. Zhang [Internat. J. Theoret. Phys., 2006, in press].Comment: 10 page
Analysis of chromosome aberrations by FISH and Giemsa assays in lymphocytes of cancer patients undergoing whole-body irradiation: comparison of in vivo and in vitro irradiation
Abstract. Studies of the frequencies of chromosome exchange aberrations in peripheral lymphocytes provide useful Purpose : To study the cytogenetic eVects of fractionated radiobiodosimetric information (IAEA 1986, Darroudi therapy in peripheral blood lymphocytes of ve cancer patients. 2000). For individual dose estimation, a calibration In vitro experiments were performed in parallel using the same dose-response curve constructed for human lympho- patients undergoing protracted whole-body irradiGiemsa-stained preparations were used to score unstable ation at low doses before local radiotherapy at high aberrations following in vivo and in vitro exposure. dose. Results: A linear dose-response curve was determined for both dicentrics and translocations. The in vivo frequency of translocations was higher than for dicentrics. Dose-response curves Materials and methods generated for translocations following in vivo and in vitro irradiation yielded similar frequencies. In contrast, for dicentrics, in 2.1. Subjects vitro irradiation yielded a higher frequency when compared with data generated following in vivo exposure. The study was performed on ve patients aged Conclusions : For dose reconstruction purposes, translocations fre-23-70 years, one woman and four men, with quency seems to be a more adequate end-point than the scoring advanced cancers and distant metastases
Предоперационная кинетика простатспецифического антигена как ф актор прогноза безрецидивной выживаемости после радикальной прост атэктомии
Objectivе. The purpose of the study – to estimate the prognostic value of preoperative prostate-specific antigen (PSA) doubling time (PSADT) in patients with prostate cancer (PCa) after radical prostatectomy (RP).Materials and Methods. The preoperative PSADT was determined in 92 patients with PCa who underwent RP in FSBI RRCRST. Incidence of biochemical recurrence and adverse pathologic features after surgery (positive lymph nodes and surgical margins, locally advanced and poorly differentiated tumors) were estimate according to the level of preoperative PSADT.Results. The correlation between the preoperative PSA kinetics and postoperative pathological findings after radical prostatectomy was shown. Positive lymph nodes (p = 0.04), locally advanced (p = 0.03) and poorly differentiated tumors (p = 0.046) were significantly more frequent in patients with a PSADT ≤ 20,0 months. The role of preoperative PSADT as a predict of relapse-free survival after radical prostatectomy was confirmed. By multivariate analysis preoperative PSADT ≤ 20 months showed a statistically significant increase in the relative risk of biochemical recurrence.Цель исследования – оценка прогностического значения предоперационного времени удвоения простатспецифического антигена (ВУПСА) у больных раком предстательной железы (РПЖ), перенесших радикальную простатэктомию (РПЭ).Материалы и методы. Предоперационное ВУПСА определено у 92 больных РПЖ, перенесших РПЭ в ФГБУ РНЦРХТ. Оценивалась частота выявления биохимического рецидива (БХР) и неблагоприятных гистологических находок после оперативного лечения (поражение лимфатических узлов, положительный хирургический край, местно-распространенные и низкодифференцированные опухоли) в зависимости от предоперационного ВУПСА.Результаты. Выявлена корреляция между исходной кинетикой ПСА и послеоперационными патологическими находками после РПЭ. У больных с ВУПСА ≤ 20,0 мес достоверно чаще выявлялись опухолевое поражение удаленных регионарных лимфатических узлов (р = 0,04), местное распространение (р = 0,03) и низкодифференцированные опухоли (р = 0,046). Подтверждена роль предоперационного ВУПСА в качестве фактора прогноза безрецидивной выживаемости после РПЭ. По результатам многофакторного анализа предоперационное ВУПСА ≤ 20 мес показало статистически значимое повышение относительных рисков развития БХР
Twisted convolution and Moyal star product of generalized functions
We consider nuclear function spaces on which the Weyl-Heisenberg group acts
continuously and study the basic properties of the twisted convolution product
of the functions with the dual space elements. The final theorem characterizes
the corresponding algebra of convolution multipliers and shows that it contains
all sufficiently rapidly decreasing functionals in the dual space.
Consequently, we obtain a general description of the Moyal multiplier algebra
of the Fourier-transformed space. The results extend the Weyl symbol calculus
beyond the traditional framework of tempered distributions.Comment: LaTeX, 16 pages, no figure
Analytical solution of second Stokes problem of behaviour of rarefied gas with Cercignani boundary accomodation conditions
Analytical solution of second Stokes problem of behaviour of rarefied gas
with Cercignani boundary accomodation conditions The second Stokes problem
about behaviour of rarefied gas filling half-space is analytically solved. A
plane, limiting half-space, makes harmonious fluctuations in the plane. The
kinetic BGK-equation (Bhatnagar, Gross, Krook) is used. The boundary
accomodation conditions of Cercignani of reflexion gaseous molecules from a
wall are considered. Distribution function of the gaseous molecules is
constructed. The velocity of gas in half-space is found, also its value direct
at a wall is found. The force resistance operating from gas on border is found.
Besides, the capacity of dissipation of the energy falling to unit of area of
the fluctuating plate limiting gas is obtained.Comment: 26 pages, 5 figure
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