53 research outputs found
Current status of turbulent dynamo theory: From large-scale to small-scale dynamos
Several recent advances in turbulent dynamo theory are reviewed. High
resolution simulations of small-scale and large-scale dynamo action in periodic
domains are compared with each other and contrasted with similar results at low
magnetic Prandtl numbers. It is argued that all the different cases show
similarities at intermediate length scales. On the other hand, in the presence
of helicity of the turbulence, power develops on large scales, which is not
present in non-helical small-scale turbulent dynamos. At small length scales,
differences occur in connection with the dissipation cutoff scales associated
with the respective value of the magnetic Prandtl number. These differences are
found to be independent of whether or not there is large-scale dynamo action.
However, large-scale dynamos in homogeneous systems are shown to suffer from
resistive slow-down even at intermediate length scales. The results from
simulations are connected to mean field theory and its applications. Recent
work on helicity fluxes to alleviate large-scale dynamo quenching, shear
dynamos, nonlocal effects and magnetic structures from strong density
stratification are highlighted. Several insights which arise from analytic
considerations of small-scale dynamos are discussed.Comment: 36 pages, 11 figures, Spa. Sci. Rev., submitted to the special issue
"Magnetism in the Universe" (ed. A. Balogh
ΠΠ ΠΠΠ’ΠΠ§ΠΠ‘ΠΠΠ ΠΠ ΠΠΠΠΠΠΠΠ ΠΠΠΠΠΠΠΠ‘ΠΠΠ Π ΠΠΠΠ ΠΠ€ΠΠ Π ΠΠΠ ΠΠΠΠΠΠΠΠ β ΠΠΠΠ«Π ΠΠΠΠ₯ΠΠΠ«
Background: The impedance rheocardiography is aΒ simple, inexpensive, noninvasive method of assessment of central hemodynamics that can be used for detection of cardiovascular remodeling and thus promote an improvement of cardiovascular mortality. Modern mathematical methods of data management could help to discover new possibilities of rheographic signal analysis. Aim: To demonstrate the potential of aΒ wavelet-analysis of rheocardiograms for identification of myocardial remodeling of patients with cardiovascular disorders. Materials and methods: The proposed method was validated in 12Β healthy men aged from 20Β to 25Β years and 14Β patients with arterial hypertension. We used aΒ polyreocardiograph, which records simultaneously the impedance (ICG), the electrocardiogram (ECG) and the phonogram (PCG). The function of the cardiovascular system was assessed based on the two-dimensional time-frequency distributions of wavelet transformed coefficients of differential rheogram curves. Results: The results of an isometric load test confirm the adequacy of stroke volume estimation based on the amplitude of wavelet coefficients and the scale of the E wave. In this technique, ISTI parameter was defined as the time interval between the R wave in the ECG and the maximum of the E wave in the wavelet image. The simultaneous time-frequency analysis of both the pulse and respiratory component of an ICG signal can be aΒ basis for the development of complex functional respiratory tests. Conclusion: The approach proposed demonstrates the possibility to obtain the characteristics of the diastolic phase of the cardiac cycle, and allows for aΒ more precise determination of the stroke volume. Data management is done automatically. These advantages are expected to be used for producing aΒ mobile cardiograph for screening diagnostic.ΠΠΊΡΡΠ°Π»ΡΠ½ΠΎΡΡΡ. ΠΠΌΠΏΠ΅Π΄Π°Π½ΡΠ½Π°Ρ ΡΠ΅ΠΎΠΊΠ°ΡΠ΄ΠΈΠΎΠ³ΡΠ°ΡΠΈΡΒ β ΠΏΡΠΎΡΡΠΎΠΉ, Π½Π΅Π΄ΠΎΡΠΎΠ³ΠΎΠΉ, Π½Π΅ΠΈΠ½Π²Π°Π·ΠΈΠ²Π½ΡΠΉ ΠΌΠ΅ΡΠΎΠ΄ ΠΈΠ·ΡΡΠ΅Π½ΠΈΡ ΡΠ΅Π½ΡΡΠ°Π»ΡΠ½ΠΎΠΉ Π³Π΅ΠΌΠΎΠ΄ΠΈΠ½Π°ΠΌΠΈΠΊΠΈ, ΠΊΠΎΡΠΎΡΡΠΉ ΠΌΠΎΠΆΠ΅Ρ Π±ΡΡΡ ΠΈΡΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°Π½ Π΄Π»Ρ Π²ΡΡΠ²Π»Π΅Π½ΠΈΡ ΠΏΡΠΎΡΠ΅ΡΡΠ° ΡΠ΅ΠΌΠΎΠ΄Π΅Π»ΠΈΡΠΎΠ²Π°Π½ΠΈΡ ΡΠ΅ΡΠ΄Π΅ΡΠ½ΠΎ-ΡΠΎΡΡΠ΄ΠΈΡΡΠΎΠΉ ΡΠΈΡΡΠ΅ΠΌΡ ΠΈΒ ΡΠΏΠΎΡΠΎΠ±ΡΡΠ²ΠΎΠ²Π°ΡΡ ΡΠ½ΠΈΠΆΠ΅Π½ΠΈΡ ΡΠΌΠ΅ΡΡΠ½ΠΎΡΡΠΈ ΠΎΡ ΡΠ΅ΡΠ΄Π΅ΡΠ½ΠΎ-ΡΠΎΡΡΠ΄ΠΈΡΡΡΡ
Π·Π°Π±ΠΎΠ»Π΅Π²Π°Π½ΠΈΠΉ. Π‘ΠΎΠ²ΡΠ΅ΠΌΠ΅Π½Π½ΡΠ΅ ΠΌΠ°ΡΠ΅ΠΌΠ°ΡΠΈΡΠ΅ΡΠΊΠΈΠ΅ ΠΌΠ΅ΡΠΎΠ΄Ρ ΠΎΠ±ΡΠ°Π±ΠΎΡΠΊΠΈ Π΄Π°Π½Π½ΡΡ
ΠΏΠΎΠ·Π²ΠΎΠ»ΡΡΡ ΠΎΡΠΊΡΡΡΡ Π½ΠΎΠ²ΡΠ΅ Π²ΠΎΠ·ΠΌΠΎΠΆΠ½ΠΎΡΡΠΈ Π°Π½Π°Π»ΠΈΠ·Π° ΡΠ΅ΠΎΠ³ΡΠ°ΡΠΈΡΠ΅ΡΠΊΠΈΡ
ΡΠΈΠ³Π½Π°Π»ΠΎΠ². Π¦Π΅Π»ΡΒ β ΠΏΠΎΠΊΠ°Π·Π°ΡΡ Π²ΠΎΠ·ΠΌΠΎΠΆΠ½ΠΎΡΡΠΈ Π²Π΅ΠΉ- Π²Π»Π΅Ρ-ΠΎΠ±ΡΠ°Π±ΠΎΡΠΊΠΈ ΡΠ΅ΠΎΠ³ΡΠ°ΡΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΡΠΈΠ³Π½Π°Π»Π° Π΄Π»Ρ ΠΏΠΎΠ»ΡΡΠ΅Π½ΠΈΡ ΠΈΠ½ΡΠΎΡΠΌΠ°ΡΠΈΠΈ ΠΎΒ ΡΠ΅ΠΌΠΎΠ΄Π΅Π»ΠΈΡΠΎΠ²Π°Π½ΠΈΠΈ ΠΌΠΈΠΎΠΊΠ°ΡΠ΄Π° Π±ΠΎΠ»ΡΠ½ΡΡ
ΡΒ ΡΠ΅ΡΠ΄Π΅ΡΠ½ΠΎ-ΡΠΎΡΡΠ΄ΠΈΡΡΡΠΌΠΈ Π·Π°Π±ΠΎΠ»Π΅Π²Π°Π½ΠΈΡΠΌΠΈ. ΠΠ°ΡΠ΅ΡΠΈΠ°Π» ΠΈΒ ΠΌΠ΅ΡΠΎΠ΄Ρ. ΠΠ»Ρ Π²Π΅ΡΠΈΡΠΈΠΊΠ°ΡΠΈΠΈ ΠΌΠ΅ΡΠΎΠ΄Π° ΠΏΡΠΎΠ²Π΅Π΄Π΅Π½ΠΎ ΠΎΠ±ΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΠ΅ 12Β Π·Π΄ΠΎΡΠΎΠ²ΡΡ
ΠΌΡΠΆΡΠΈΠ½ Π²Β Π²ΠΎΠ·ΡΠ°ΡΡΠ΅ ΠΎΡΒ 20 Π΄ΠΎΒ 25Β Π»Π΅Ρ, ΡΠΎΡΡΠ°Π²ΠΈΠ²ΡΠΈΡ
Π³ΡΡΠΏΠΏΡ ΠΊΠΎΠ½ΡΡΠΎΠ»Ρ, ΠΈΒ 14Β ΠΏΠ°ΡΠΈΠ΅Π½ΡΠΎΠ² ΡΒ Π΄ΠΈΠ°Π³Π½ΠΎΠ·ΠΎΠΌ Π³ΠΈΠΏΠ΅ΡΡΠΎΠ½ΠΈΡΠ΅ΡΠΊΠΎΠΉ Π±ΠΎΠ»Π΅Π·Π½ΠΈ. ΠΡΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°Π»ΡΡ ΠΌΠ΅ΡΠΎΠ΄ ΠΏΠΎΠ»ΠΈΡΠ΅ΠΎΠΊΠ°ΡΠ΄ΠΈΠΎΠ³ΡΠ°ΡΠΈΠΈ, Π²Β ΠΊΠΎΡΠΎΡΠΎΠΌ ΠΎΠ΄Π½ΠΎΠ²ΡΠ΅ΠΌΠ΅Π½Π½ΠΎ ΡΒ ΠΈΠΌΠΏΠ΅Π΄Π°Π½ΡΠ½ΠΎΠΉ ΡΠ΅ΠΎΠΊΠ°ΡΠ΄ΠΈΠΎΠ³ΡΠ°ΠΌΠΌΠΎΠΉ ΡΠ΅Π³ΠΈΡΡΡΠΈΡΠΎΠ²Π°Π»ΠΈΡΡ ΡΠ»Π΅ΠΊΡΡΠΎ- ΠΊΠ°ΡΠ΄ΠΈΠΎΠ³ΡΠ°ΠΌΠΌΠ° ΠΈΒ ΡΠΎΠ½ΠΎΠΊΠ°ΡΠ΄ΠΈΠΎΠ³ΡΠ°ΠΌΠΌΠ°. ΠΡΠ»Π° ΠΈΡΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°Π½Π° ΠΌΠ΅ΡΠΎΠ΄ΠΈΠΊΠ° ΠΎΡΠ΅Π½ΠΊΠΈ ΡΡΠ½ΠΊΡΠΈΠΎΠ½Π°Π»ΡΠ½ΠΎΠ³ΠΎ ΡΠΎΡΡΠΎΡΠ½ΠΈΡ ΡΠ΅ΡΠ΄Π΅ΡΠ½ΠΎ-ΡΠΎΡΡΠ΄ΠΈΡΡΠΎΠΉ ΡΠΈΡΡΠ΅ΠΌΡ Π½Π° ΠΎΡΠ½ΠΎΠ²Π΅ Π°Π½Π°Π»ΠΈΠ·Π° Π΄Π²ΡΡ
ΠΌΠ΅ΡΠ½ΡΡ
ΡΠ°ΡΡΠΎΡΠ½ΠΎ-Π²ΡΠ΅ΠΌΠ΅Π½Π½ΡΡ
ΡΠ°ΡΠΏΡΠ΅Π΄Π΅Π»Π΅Π½ΠΈΠΉ Π²Π΅ΠΉΠ²Π»Π΅Ρ-ΠΊΠΎΡΡΡΠΈΡΠΈΠ΅Π½ΡΠΎΠ² ΠΏΡΠ΅ΠΎΠ±ΡΠ°Π·ΠΎΠ²Π°Π½ΠΈΡ ΠΊΡΠΈΠ²ΡΡ
Π΄ΠΈΡΡΠ΅ΡΠ΅Π½ΡΠΈΠ°Π»ΡΠ½ΠΎΠΉ ΡΠ΅ΠΎΠ³ΡΠ°ΠΌΠΌΡ. Π Π΅Π·ΡΠ»ΡΡΠ°ΡΡ. ΠΠ°Π½Π½ΡΠ΅ Π½Π°Π³ΡΡΠ·ΠΎΡΠ½ΠΎΠ³ΠΎ ΠΈΠ·ΠΎΠΌΠ΅ΡΡΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΡΠ΅ΡΡΠ° ΠΏΠΎΠ΄ΡΠ²Π΅ΡΠΆΠ΄Π°ΡΡ Π°Π΄Π΅ΠΊΠ²Π°ΡΠ½ΠΎΡΡΡ ΠΎΠΏΡΠ΅Π΄Π΅Π»Π΅Π½ΠΈΡ ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΠ° ΡΠ΄Π°ΡΠ½ΠΎΠ³ΠΎ ΠΎΠ±ΡΠ΅ΠΌΠ° Π½Π° ΠΎΡΠ½ΠΎΠ²Π΅ Π°ΠΌΠΏΠ»ΠΈΡΡΠ΄ Π²Π΅ΠΉΠ²Π»Π΅Ρ-ΠΊΠΎΡΡΡΠΈΡΠΈΠ΅Π½ΡΠΎΠ² ΠΈΒ ΠΌΠ°ΡΡΡΠ°Π±Π° Π-Π²ΠΎΠ»Π½Ρ. ΠΠ°ΡΠ°ΠΌΠ΅ΡΡ ISTI Π²Β ΡΠ°ΠΌΠΊΠ°Ρ
ΡΡΠΎΠ³ΠΎ ΠΏΠΎΠ΄Ρ
ΠΎΠ΄Π° ΠΎΠΏΡΠ΅Π΄Π΅Π»ΡΠ΅ΡΡΡ ΠΊΠ°ΠΊ Π²ΡΠ΅ΠΌΠ΅Π½Π½ΠΎΠΉ ΠΈΠ½ΡΠ΅ΡΠ²Π°Π» ΠΌΠ΅ΠΆΠ΄Ρ R-ΠΏΠΈΠΊΠΎΠΌ ΡΠ»Π΅ΠΊΡΡΠΎΠΊΠ°ΡΠ΄ΠΈΠΎΠ³ΡΠ°ΠΌΠΌΡ ΠΈΒ ΠΌΠ°ΠΊΡΠΈΠΌΡΠΌΠΎΠΌ Π²Π΅ΠΉΠ²Π»Π΅Ρ-ΠΏΡΠ΅Π΄ΡΡΠ°Π²Π»Π΅Π½ΠΈΡ Π-Π²ΠΎΠ»Π½Ρ. ΠΠ΄Π½ΠΎΠ²ΡΠ΅ΠΌΠ΅Π½Π½ΡΠΉ ΡΠ°ΡΡΠΎΡΠ½ΠΎ-Π²ΡΠ΅ΠΌΠ΅Π½Π½ΠΎΠΉ Π°Π½Π°Π»ΠΈΠ· ΠΊΠ°ΠΊ ΠΏΡΠ»ΡΡΠΎΠ²ΠΎΠΉ, ΡΠ°ΠΊ ΠΈΒ Π΄ΡΡ
Π°ΡΠ΅Π»ΡΠ½ΠΎΠΉ ΡΠΎΡΡΠ°Π²Π»ΡΡΡΠ΅ΠΉ ΡΠ΅ΠΎΠ³ΡΠ°ΡΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΡΠΈΠ³Π½Π°Π»Π° ΠΌΠΎΠΆΠ΅Ρ ΡΠ»ΡΠΆΠΈΡΡ ΠΎΡΠ½ΠΎΠ²ΠΎΠΉ Π΄Π»Ρ ΡΠ°Π·ΡΠ°Π±ΠΎΡΠΊΠΈ ΠΊΠΎΠΌΠΏΠ»Π΅ΠΊΡΠ° ΡΡΠ½ΠΊΡΠΈΠΎΠ½Π°Π»ΡΠ½ΡΡ
ΡΠ΅ΡΡΠΎΠ² Π½Π° ΠΎΡΠ½ΠΎΠ²Π΅ Π΄ΡΡ
Π°Π½ΠΈΡ. ΠΠ°ΠΊΠ»ΡΡΠ΅Π½ΠΈΠ΅. ΠΡΠ΅Π΄Π»Π°Π³Π°Π΅ΠΌΡΠΉ ΠΏΠΎΠ΄Ρ
ΠΎΠ΄ ΠΏΠΎΠΊΠ°Π·ΡΠ²Π°Π΅Ρ Π²ΠΎΠ·ΠΌΠΎΠΆΠ½ΠΎΡΡΡ ΠΏΠΎΠ»ΡΡΠ΅Π½ΠΈΡ Ρ
Π°ΡΠ°ΠΊΡΠ΅ΡΠΈΡΡΠΈΠΊ Π΄ΠΈΠ°ΡΡΠΎΠ»ΠΈΡΠ΅ΡΠΊΠΎΠΉ ΡΠ°Π·Ρ ΡΠ΅ΡΠ΄Π΅ΡΠ½ΠΎΠ³ΠΎ ΡΠΈΠΊΠ»Π° ΠΈΒ ΠΏΠΎΠ·Π²ΠΎΠ»ΡΠ΅Ρ ΡΡΠΎΡΠ½ΠΈΡΡ ΠΎΠΏΡΠ΅Π΄Π΅Π»Π΅Π½ΠΈΠ΅ ΡΠ΄Π°ΡΠ½ΠΎΠ³ΠΎ ΠΎΠ±ΡΠ΅ΠΌΠ°. ΠΠ±ΡΠ°Π±ΠΎΡΠΊΠ° Π΄Π°Π½Π½ΡΡ
ΠΏΡΠΎΡ
ΠΎΠ΄ΠΈΡ Π²Β Π°Π²ΡΠΎΠΌΠ°ΡΠΈΡΠ΅ΡΠΊΠΎΠΌ ΡΠ΅ΠΆΠΈΠΌΠ΅. ΠΡΠΈ ΠΏΡΠ΅ΠΈΠΌΡΡΠ΅ΡΡΠ²Π° ΠΏΡΠ΅Π΄ΠΏΠΎΠ»Π°Π³Π°Π΅ΡΡΡ ΠΈΡΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°ΡΡ ΠΏΡΠΈ ΡΠΎΠ·Π΄Π°Π½ΠΈΠΈ ΠΌΠΎΠ±ΠΈΠ»ΡΠ½ΠΎΠ³ΠΎ ΠΊΠ°ΡΠ΄ΠΈΠΎΠ³ΡΠ°ΡΠ° Π΄Π»Ρ ΡΠΊΡΠΈΠ½ΠΈΠ½Π³ΠΎΠ²ΠΎΠΉ Π΄ΠΈΠ°Π³Π½ΠΎΡΡΠΈΠΊΠΈ.
Deflections of cosmic rays in a random component of the galactic magnetic field
We express the mean square deflections of the ultra-high energy cosmic rays (UHECR) caused by the random component of the Galactic magnetic field (GMF) in terms of the GMF power spectrum. We use recent measurements of the GMF spectra in several sky patches to estimate the deflections quantitatively. We find that deflections due to the random field constitute 0.03-0.3 of the deflections which are due to the regular component and depend on the direction on the sky. They are small enough not to preclude the identification of UHECR sources, but large enough to be detected in the new generation of UHECR experiments. Β© 2005 Elsevier B.V. All rights reserved.SCOPUS: ar.jinfo:eu-repo/semantics/publishe
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