412 research outputs found
Resonances and O-curves in Hamiltonian systems
We investigate the problem of the existence of trajectories asymptotic to
elliptic equilibria of Hamiltonian systems in the presence of resonances.Comment: 12 page
Π‘ΠΎΠ²ΡΠ΅ΠΌΠ΅Π½Π½ΡΠ΅ ΠΊΠ»ΠΈΠ½ΠΈΠΊΠΎ-ΠΌΠΎΡΡΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΈΠ΅ Π°ΡΠΏΠ΅ΠΊΡΡ ΠΈΠ·ΡΡΠ΅Π½ΠΈΡ ΡΠ°ΡΡΡΡΠΎΠΉΡΡΠ² ΠΌΠΈΠΊΡΠΎΡΠΈΡΠΊΡΠ»ΡΡΠΈΠΈ ΠΊΡΠΎΠ²ΠΈ
Modern data about microcirculation disorders are presented. The methodical base of carrying out clinical-morphological and functional researches of microcirculation is discussed. The individual typological features of microcirculation caused by active and passive mechanisms of modulation of a tissue blood flow are revealed. The characteristics of different forms of microcirculation disorders (hyperemic, spastic, spastic-atonic, stagnat and stasic forms) are given. Classification of microcirculation disorders, including four degree of insufficiency of tissue blood flow is offered.ΠΡΠ΅Π΄ΡΡΠ°Π²Π»Π΅Π½Ρ ΡΠΎΠ²ΡΠ΅ΠΌΠ΅Π½Π½ΡΠ΅ ΡΠ²Π΅Π΄Π΅Π½ΠΈΡ ΠΎ Π΄ΠΈΠ°Π³Π½ΠΎΡΡΠΈΠΊΠ΅ ΡΠ°ΡΡΡΡΠΎΠΉΡΡΠ²Π°Ρ
ΠΌΠΈΠΊΡΠΎΡΠΈΡΠΊΡΠ»ΡΡΠΈΠΈ ΠΊΡΠΎΠ²ΠΈ. ΠΡΡΠ²Π»Π΅Π½Ρ ΠΈΠ½Π΄ΠΈΠ²ΠΈΠ΄ΡΠ°Π»ΡΠ½ΠΎ-ΡΠΈΠΏΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΈΠ΅ ΠΎΡΠΎΠ±Π΅Π½Π½ΠΎΡΡΠΈ ΠΌΠΈΠΊΡΠΎΡΠΈΡΠΊΡΠ»ΡΡΠΈΠΈ, ΠΎΠ±ΡΡΠ»ΠΎΠ²Π»Π΅Π½Π½ΡΠ΅ ΡΠ°Π·Π»ΠΈΡΠ½ΡΠΌ ΡΡΠΎΠ²Π½Π΅ΠΌ ΡΠΊΠ°Π½Π΅Π²ΠΎΠ³ΠΎ ΠΊΡΠΎΠ²ΠΎΡΠΎΠΊΠ° ΠΈ ΡΠ°Π·Π½ΡΠΌΠΈ ΠΌΠ΅Ρ
Π°Π½ΠΈΠ·ΠΌΠ°ΠΌΠΈ Π΅Π³ΠΎ ΠΌΠΎΠ΄ΡΠ»ΡΡΠΈΠΈ. ΠΠ°Π½Π° Ρ
Π°ΡΠ°ΠΊΡΠ΅ΡΠΈΡΡΠΈΠΊΠ° ΡΠ°Π·Π»ΠΈΡΠ½ΡΡ
ΡΠΎΡΠΌ ΡΠ°ΡΡΡΡΠΎΠΉΡΡΠ² ΠΌΠΈΠΊΡΠΎΡΠΈΡΠΊΡΠ»ΡΡΠΈΠΈ: Π³ΠΈΠΏΠ΅ΡΠ΅ΠΌΠΈΡΠ΅ΡΠΊΠΎΠΉ, ΡΠΏΠ°ΡΡΠΈΡΠ΅ΡΠΊΠΎΠΉ, ΡΠΏΠ°ΡΡΠΈΠΊΠΎ-Π°ΡΠΎΠ½ΠΈΡΠ΅ΡΠΊΠΎΠΉ, Π·Π°ΡΡΠΎΠΉΠ½ΠΎΠΉ ΠΈ ΡΡΠ°Π·ΠΈΡΠ΅ΡΠΊΠΎΠΉ. ΠΡΠ΅Π΄Π»ΠΎΠΆΠ΅Π½Π° ΠΊΠ»Π°ΡΡΠΈΡΠΈΠΊΠ°ΡΠΈΡ ΡΠ°ΡΡΡΡΠΎΠΉΡΡΠ² ΠΌΠΈΠΊΡΠΎΡΠΈΡΠΊΡΠ»ΡΡΠΈΠΈ, ΠΎΡΠ½ΠΎΠ²Π°Π½Π½Π°Ρ Π½Π° ΡΡΠ΅ΠΏΠ΅Π½ΡΡ
Π΄Π΅ΠΊΠΎΠΌΠΏΠ΅Π½ΡΠ°ΡΠΈΠΈ ΡΠΊΠ°Π½Π΅Π²ΠΎΠ³ΠΎ ΠΊΡΠΎΠ²ΠΎΡΠΎΠΊΠ°
Stability estimates for resolvents, eigenvalues and eigenfunctions of elliptic operators on variable domains
We consider general second order uniformly elliptic operators subject to
homogeneous boundary conditions on open sets parametrized by
Lipschitz homeomorphisms defined on a fixed reference domain .
Given two open sets , we estimate the
variation of resolvents, eigenvalues and eigenfunctions via the Sobolev norm
for finite values of , under
natural summability conditions on eigenfunctions and their gradients. We prove
that such conditions are satisfied for a wide class of operators and open sets,
including open sets with Lipschitz continuous boundaries. We apply these
estimates to control the variation of the eigenvalues and eigenfunctions via
the measure of the symmetric difference of the open sets. We also discuss an
application to the stability of solutions to the Poisson problem.Comment: 34 pages. Minor changes in the introduction and the refercenes.
Published in: Around the research of Vladimir Maz'ya II, pp23--60, Int. Math.
Ser. (N.Y.), vol. 12, Springer, New York 201
ΠΡΠΎΠ±Π΅Π½Π½ΠΎΡΡΠΈ ΠΌΠΈΠΊΡΠΎΡΠΈΡΠΊΡΠ»ΡΡΠΈΠΈ ΠΊΡΠΎΠ²ΠΈ Π² ΠΊΠΎΠΆΠ΅ Ρ Π΄Π΅ΡΠ΅ΠΉ
The characteristics of a skin blood microcirculation by method of laser Doppler flowmetry (LDF) in 70 children at the age from 4 till 7 years are studied. During this period of life, gradual decrease in intensity of blood microcirculation in the skin is observed. For surveyed children three types of microcirculation are characteristic: mesohaemic, hypohaemic and hiperhaemic. Mesohaemic type of microcirculation (51,4% of children) prevails with balanced sympathetic and parasympathetic regulatory influences.ΠΠ΅ΡΠΎΠ΄ΠΎΠΌ Π»Π°Π·Π΅ΡΠ½ΠΎΠΉ Π΄ΠΎΠΏΠ»Π΅ΡΠΎΠ²ΡΠΊΠΎΠΉ ΡΠ»ΠΎΡΠΌΠ΅ΡΡΠΈΠΈ (ΠΠΠ€) ΠΈΠ·ΡΡΠ΅Π½ΠΎ ΡΠΎΡΡΠΎΡΠ½ΠΈΠ΅ ΠΊΠΎΠΆΠ½ΠΎΠ³ΠΎ ΠΊΡΠΎΠ²ΠΎΡΠΎΠΊΠ° Ρ 70 Π΄Π΅ΡΠ΅ΠΉ Π² Π²ΠΎΠ·ΡΠ°ΡΡΠ΅ ΠΎΡ 4 Π΄ΠΎ 7 Π»Π΅Ρ. Π ΡΡΠΎΡ ΠΏΠ΅ΡΠΈΠΎΠ΄ Π½Π°Π±Π»ΡΠ΄Π°Π΅ΡΡΡ ΠΏΠΎΡΡΠ΅ΠΏΠ΅Π½Π½ΠΎΠ΅ ΡΠ½ΠΈΠΆΠ΅Π½ΠΈΠ΅ ΠΈΠ½ΡΠ΅Π½ΡΠΈΠ²Π½ΠΎΡΡΠΈ ΠΊΡΠΎΠ²ΠΎΡΠΎΠΊΠ° Π² ΠΊΠΎΠΆΠ΅. ΠΠ»Ρ ΠΎΠ±ΡΠ»Π΅Π΄ΠΎΠ²Π°Π½Π½ΡΡ
Π΄Π΅ΡΠ΅ΠΉ Ρ
Π°ΡΠ°ΠΊΡΠ΅ΡΠ½Ρ ΡΡΠΈ ΡΠΈΠΏΠ° ΠΌΠΈΠΊΡΠΎΡΠΈΡΠΊΡΠ»ΡΡΠΈΠΈ: ΠΌΠ΅Π·ΠΎΠ΅ΠΌΠΈΡΠ΅ΡΠΊΠΈΠΉ, Π³ΠΈΠΏΠΎΠ΅ΠΌΠΈΡΠ΅ΡΠΊΠΈΠΉ ΠΈ Π³ΠΈΠΏΠ΅ΡΠ΅ΠΌΠΈΡΠ΅ΡΠΊΠΈΠΉ. ΠΡΠ΅ΠΎΠ±Π»Π°Π΄Π°Π΅Ρ ΠΌΠ΅Π·ΠΎΠ΅ΠΌΠΈΡΠ΅ΡΠΊΠΈΠΉ ΡΠΈΠΏ ΠΌΠΈΠΊΡΠΎΡΠΈΡΠΊΡΠ»ΡΡΠΈΠΈ (51,4% Π΄Π΅ΡΠ΅ΠΉ), ΠΏΡΠΈ ΠΊΠΎΡΠΎΡΠΎΠΌ ΡΠ΅Π³ΡΠ»ΡΡΠΎΡΠ½ΡΠ΅ Π²Π»ΠΈΡΠ½ΠΈΡ ΡΠ±Π°Π»Π°Π½ΡΠΈΡΠΎΠ²Π°Π½Ρ
Experimental limits on the proton life-time from the neutrino experiments with heavy water
Experimental data on the number of neutrons born in the heavy water targets
of the large neutrino detectors are used to set the limit on the proton
life-time independently on decay mode through the reaction d -> n+?. The best
up-to-date limit tau_p > 4 10^23 yr with 95% C.L. is derived from the
measurements with D_2O target (mass 267 kg) installed near the Bugey reactor.
This value can be improved by six orders of magnitude with future data
accumulated with the SNO detector containing 1000 t of D_2O.Comment: LaTeX, 7 pages, 1 table; small typo is correcte
Complex assessment of parameters of central hemodynamics and microcirculation in children of 6-7 years old
The paper presents the results of a comprehensive assessment of central hemodynamic and microcirculation indices in the skin of upper and lower limbs in 6β7-year-old children. 14 girls and 7 boys were examined using laser Doppler flowmetry methods (the LASMA-PF device, allowing simultaneous recording by four sensors) and the analysis of heart rate variability ("Varicard"). The parameters characterizing microcirculation in the limbs were determined and the signs of the appearing functional asymmetry of the upper limbs, as well as the differences in the mechanisms of modulation of cutaneous blood flow in boys and girls were revealed. The estimation of heart rate variability reveals the signs of girls' inclination to sympathotony and boys' inclination to vagotony at the given age. It was marked that central regulation mechanisms have the greater contribution to cardiac rhythm formation in girls. The data obtained testify to the fact that age-related changes at different levels of the cardiovascular system and regulation mechanisms occur somewhat earlier in girls than in boys
The last integrable case of kozlov-Treshchev Birkhoff integrable potentials
We establish the integrability of the last open case in the Kozlov-Treshchev
classification of Birkhoff integrable Hamiltonian systems. The technique used
is a modification of the so called quadratic Lax pair for Toda lattice
combined with a method used by M. Ranada in proving the integrability of the
Sklyanin case.Comment: 13 page
The Dynamics of a Rigid Body in Potential Flow with Circulation
We consider the motion of a two-dimensional body of arbitrary shape in a
planar irrotational, incompressible fluid with a given amount of circulation
around the body. We derive the equations of motion for this system by
performing symplectic reduction with respect to the group of volume-preserving
diffeomorphisms and obtain the relevant Poisson structures after a further
Poisson reduction with respect to the group of translations and rotations. In
this way, we recover the equations of motion given for this system by Chaplygin
and Lamb, and we give a geometric interpretation for the Kutta-Zhukowski force
as a curvature-related effect. In addition, we show that the motion of a rigid
body with circulation can be understood as a geodesic flow on a central
extension of the special Euclidian group SE(2), and we relate the cocycle in
the description of this central extension to a certain curvature tensor.Comment: 28 pages, 2 figures; v2: typos correcte
Contact complete integrability
Complete integrability in a symplectic setting means the existence of a
Lagrangian foliation leaf-wise preserved by the dynamics. In the paper we
describe complete integrability in a contact set-up as a more subtle structure:
a flag of two foliations, Legendrian and co-Legendrian, and a
holonomy-invariant transverse measure of the former in the latter. This turns
out to be equivalent to the existence of a canonical
structure on the leaves of the co-Legendrian foliation. Further, the above
structure implies the existence of contact fields preserving a special
contact 1-form, thus providing the geometric framework and establishing
equivalence with previously known definitions of contact integrability. We also
show that contact completely integrable systems are solvable in quadratures. We
present an example of contact complete integrability: the billiard system
inside an ellipsoid in pseudo-Euclidean space, restricted to the space of
oriented null geodesics. We describe a surprising acceleration mechanism for
closed light-like billiard trajectories
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