130 research outputs found
Centrifugally driven electrostatic instability in extragalactic jets
The stability problem of the rotation induced electrostatic wave in
extragalactic jets is presented. Solving a set of equations describing dynamics
of a relativistic plasma flow of AGN jets, an expression of the instability
rate has been derived and analyzed for typical values of AGNs. The growth rate
was studied versus the wave length and the inclination angle and it has been
found that the instability process is much efficient with respect to the
accretion disk evolution, indicating high efficiency of the instability.Comment: 7 pages, 4 figure
Features of the anatomical structure of leaves depending on the high-altitude growth of apricot in Dagestan
Background.Β The adaptive changes during the distribution of Prunus armeniaca L. in Dagestan are important for understanding microevolution, structural and functional differentiation processes of populations along environmental gradients based on the organismβs reaction norm. They can be examined by studying leaf anatomical features, having ecologically differentiating significance in natural populations with contrasting growth conditions.Β Β Materials and methods.Β The material for the study of leaf anatomical features was taken from 7 apricot trees in 3 growing areas of Mountainous Dagestan. Comparative analysis was carried out for 42 morphological, anatomical and index parameters of the lamina and petiole.Β Β Results.Β The anocytic structure type of the stomatal apparatus was found in all apricot samples. The differences were determined by the degree of stomata submergence depending on the cuticleβs development. Trees from greater heights had more trichomes on the leafβs upper side than on its underside. Significant differences between the extreme height reference points were recorded for the number of stomata, cells of the lower epidermis, layers of the sclerenchyma, and xylem thickness. Most of the traits of the lamina decreased, and those of the petiole increased with the altitude.Β Β Conclusion.Β The traits corresponding to the lower and upper altitude limits of P. armeniaca were identified on the basis of the lamina and petiole anatomical features. More xerophytic leaf traits were recorded for the altitudes of 550 m and 1900 m, and mesophytic ones for 1700 m and 1800 m. Endoderm thickness, number of endosperm layers, petiole index, and stomatal index were identified as stable indicators according to the reaction norm within the scope of altitudes: The differences were proved for more plastic traits (number of cells of the upper and lower epidermis, number of stomata, thickness of the lamina and cuticle, and the petioleβs long axis diameter)
Kelvin-Helmholtz Instability of the Magnetopause of Disc-Accreting Stars
This work investigates the short wavelength stability of the magnetopause
between a rapidly-rotating, supersonic, dense accretion disc and a
slowly-rotating low-density magnetosphere of a magnetized star. The
magnetopause is a strong shear layer with rapid changes in the azimuthal
velocity, the density, and the magnetic field over a short radial distance and
thus the Kelvin-Helmholtz (KH) instability may be important. The plasma
dynamics is treated using non-relativistic, compressible (isentropic)
magnetohydrodynamics. It is necessary to include the displacement current in
order that plasma wave velocities remain less than the speed of light. We focus
mainly on the case of a star with an aligned dipole magnetic field so that the
magnetic field is axial in the disc midplane and perpendicular to the disc flow
velocity. However, we also give results for cases where the magnetic field is
at an arbitrary angle to the flow velocity. For the aligned dipole case the
magnetopause is most unstable for KH waves propagating in the azimuthal
direction perpendicular to the magnetic field which tends to stabilize waves
propagating parallel to it. The wave phase velocity is that of the disc matter.
A quasi-linear theory of the saturation of the instability leads to a
wavenumber () power spectrum of the density and temperature
fluctuations of the magnetopause, and it gives the mass accretion and angular
momentum inflow rates across the magnetopause. For self-consistent conditions
this mass accretion rate will be equal to the disc accretion rate at large
distances from the magnetopause.Comment: 8 pages, 7 figure
The OscSNS White Paper
There exists a need to address and resolve the growing evidence for
short-baseline neutrino oscillations and the possible existence of sterile
neutrinos. Such non-standard particles require a mass of eV/c, far
above the mass scale associated with active neutrinos, and were first invoked
to explain the LSND appearance signal.
More recently, the MiniBooNE experiment has reported a excess of
events in antineutrino mode consistent with neutrino oscillations and with the
LSND antineutrino appearance signal. MiniBooNE also observed a
excess of events in their neutrino mode data. Lower than expected
neutrino-induced event rates using calibrated radioactive sources and nuclear
reactors can also be explained by the existence of sterile neutrinos. Fits to
the world's neutrino and antineutrino data are consistent with sterile
neutrinos at this eV/c mass scale, although there is some tension
between measurements from disappearance and appearance experiments. In addition
to resolving this potential major extension of the Standard Model, the
existence of sterile neutrinos will impact design and planning for all future
neutrino experiments. It should be an extremely high priority to conclusively
establish if such unexpected light sterile neutrinos exist. The Spallation
Neutron Source (SNS) at Oak Ridge National Laboratory, built to usher in a new
era in neutron research, provides a unique opportunity for US science to
perform a definitive world-class search for sterile neutrinos.Comment: This white paper is submitted as part of the SNOWMASS planning
proces
ΠΡΠΈΠΌΠ΅Π½Π΅Π½ΠΈΠ΅ ΠΎΠ·ΠΎΠ½ΠΈΡΠΎΠ²Π°Π½Π½ΠΎΠ³ΠΎ ΠΏΠ΅ΡΡΡΠΎΡΠ°Π½Π° ΠΏΡΠΈ ΠΎΡΡΡΠΎΠΌ ΠΏΠ΅ΡΠΈΡΠΎΠ½ΠΈΡΠ΅
The properties of ozonized perfluorane were first studied in the treatment of experimental generalized peritonitis. Experiments were conducted on albino noninbred rats. The model of acute peritonitis, proposed by S. S. Remennik, was used. After simulating peritonitis, the animals were intraperitoneally injected saline solution (Series 1), perfluorane (Series 2), ozonized saline solution (Series 3), ozonized perfluorane (Series 4). All the animals intraperitoneally given saline solution died on days 1β7 of the experiment. When ozonized perfluorane was used, all the animals survived. The therapeutic effect of ozonized perfluorane in acute peritonitis was due to the activation of phagocytes and to the antibacterial activity of ozone.ΠΠΏΠ΅ΡΠ²ΡΠ΅ ΠΈΠ·ΡΡΠ΅Π½Ρ ΡΠ²ΠΎΠΉΡΡΠ²Π° ΠΎΠ·ΠΎΠ½ΠΈΡΠΎΠ²Π°Π½Π½ΠΎΠ³ΠΎ ΠΏΠ΅ΡΡΡΠΎΡΠ°Π½Π° ΠΏΡΠΈ Π»Π΅ΡΠ΅Π½ΠΈΠΈ ΡΠΊΡΠΏΠ΅ΡΠΈΠΌΠ΅Π½ΡΠ°Π»ΡΠ½ΠΎΠ³ΠΎ ΡΠ°Π·Π»ΠΈΡΠΎΠ³ΠΎ ΠΏΠ΅ΡΠΈΡΠΎΠ½ΠΈΡΠ°. ΠΠΏΡΡΡ ΠΏΡΠΎΠ²Π΅Π΄Π΅Π½Ρ Π½Π° Π±Π΅Π»ΡΡ
Π±Π΅ΡΠΏΠΎΡΠΎΠ΄Π½ΡΡ
ΠΊΡΡΡΠ°Ρ
. ΠΡΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°Π»Π°ΡΡ ΠΌΠΎΠ΄Π΅Π»Ρ ΠΎΡΡΡΠΎΠ³ΠΎ ΠΏΠ΅ΡΠΈΡΠΎΠ½ΠΈΡΠ° ΠΏΠΎ Π‘. Π‘. Π Π΅ΠΌΠ΅Π½Π½ΠΈΠΊΡ. ΠΠΎΡΠ»Π΅ ΠΌΠΎΠ΄Π΅Π»ΠΈΡΠΎΠ²Π°Π½ΠΈΡ ΠΏΠ΅ΡΠΈΡΠΎΠ½ΠΈΡΠ° ΠΆΠΈΠ²ΠΎΡΠ½ΡΠΌ Π² Π±ΡΡΡΠ½ΡΡ ΠΏΠΎΠ»ΠΎΡΡΡ Π²Π²ΠΎΠ΄ΠΈΠ»ΠΈΡΡ ΡΠΈΠ·ΠΈΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΈΠΉ ΡΠ°ΡΡΠ²ΠΎΡ (1-Ρ ΡΠ΅ΡΠΈΡ), ΠΏΠ΅ΡΡΡΠΎ-ΡΠ°Π½ (2-Ρ ΡΠ΅ΡΠΈΡ), ΠΎΠ·ΠΎΠ½ΠΈΡΠΎΠ²Π°Π½Π½ΡΠΉ ΡΠΈΠ·ΠΈΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΈΠΉ ΡΠ°ΡΡΠ²ΠΎΡ (3-Ρ ΡΠ΅ΡΠΈΡ), ΠΎΠ·ΠΎΠ½ΠΈΡΠΎΠ²Π°Π½Π½ΡΠΉ ΠΏΠ΅ΡΡΡΠΎΡΠ°Π½ (4-Ρ ΡΠ΅ΡΠΈΡ). ΠΡΠ΅ ΠΆΠΈΠ²ΠΎΡΠ½ΡΠ΅, ΠΊΠΎΡΠΎΡΡΠΌ Π² Π±ΡΡΡΠ½ΡΡ ΠΏΠΎΠ»ΠΎΡΡΡ Π²Π²ΠΎΠ΄ΠΈΠ»ΠΈ ΡΠΈΠ·ΠΈΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΈΠΉ ΡΠ°ΡΡΠ²ΠΎΡ, ΠΏΠΎΠ³ΠΈΠ±Π»ΠΈ Π½Π° 1β7 ΡΡΡΠΊΠΈ ΡΠΊΡΠΏΠ΅ΡΠΈΠΌΠ΅Π½ΡΠ°. ΠΡΠΈ ΠΏΡΠΈΠΌΠ΅Π½Π΅Π½ΠΈΠΈ ΠΎΠ·ΠΎΠ½ΠΈΡΠΎΠ²Π°Π½Π½ΠΎΠ³ΠΎ ΠΏΠ΅ΡΡΡΠΎΡΠ°Π½Π° Π²ΡΠ΅ ΠΆΠΈΠ²ΠΎΡΠ½ΡΠ΅ Π²ΡΠΆΠΈΠ»ΠΈ. Π’Π΅ΡΠ°ΠΏΠ΅Π²ΡΠΈΡΠ΅ΡΠΊΠΈΠΉ ΡΡΡΠ΅ΠΊΡ ΠΎΠ·ΠΎΠ½ΠΈΡΠΎΠ²Π°Π½Π½ΠΎΠ³ΠΎ ΠΏΠ΅ΡΡΡΠΎΡΠ°Π½Π° ΠΏΡΠΈ ΠΎΡΡΡΠΎΠΌ ΠΏΠ΅ΡΠΈΡΠΎΠ½ΠΈΡΠ΅ ΠΎΠ±ΡΡΠ»ΠΎΠ²Π»Π΅Π½ Π°ΠΊΡΠΈΠ²Π°ΡΠΈΠ΅ΠΉ ΡΠ°Π³ΠΎΡΠΈΡΠΈΡΡΡΡΠΈΡ
ΠΊΠ»Π΅ΡΠΎΠΊ ΠΈ Π°Π½ΡΠΈΠ±Π°ΠΊΡΠ΅ΡΠΈΠ°Π»ΡΠ½ΡΠΌ Π΄Π΅ΠΉΡΡΠ²ΠΈΠ΅ΠΌ ΠΎΠ·ΠΎΠ½Π°
Centrifugally driven relativistic dynamics on curved trajectories
Motion of test particles along rotating curved trajectories is considered.
The problem is studied both in the laboratory and the rotating frames of
reference. It is assumed that the system rotates with the constant angular
velocity . The solutions are found and analyzed for the case
when the form of the trajectory is given by an Archimedes spiral. It is found
that particles can reach infinity while they move along these trajectories and
the physical interpretation of their behaviour is given. The analogy of this
idealized study with the motion of particles along the curved rotating magnetic
field lines in the pulsar magnetosphere is pointed out. We discuss further
physical development (the conserved total energy case, when )
and astrophysical applications (the acceleration of particles in active
galactic nuclei) of this theory.Comment: 13 pages, 3 figures, to appear in the vol.35 (July issue) of the
"General Relativity and Gravitation
Measurement of the neutrino component of an anti-neutrino beam observed by a non-magnetized detector
Two independent methods are employed to measure the neutrino flux of the
anti-neutrino-mode beam observed by the MiniBooNE detector. The first method
compares data to simulated event rates in a high purity \numu induced
charged-current single \pip (CC1\pip) sample while the second exploits the
difference between the angular distributions of muons created in \numu and
\numub charged-current quasi-elastic (CCQE) interactions. The results from
both analyses indicate the prediction of the neutrino flux component of the
pre-dominately anti-neutrino beam is over-estimated - the CC1\pip analysis
indicates the predicted \numu flux should be scaled by , while
the CCQE angular fit yields . The energy spectrum of the flux
prediction is checked by repeating the analyses in bins of reconstructed
neutrino energy, and the results show that the spectral shape is well modeled.
These analyses are a demonstration of techniques for measuring the neutrino
contamination of anti-neutrino beams observed by future non-magnetized
detectors.Comment: 15 pages, 7 figures, published in Physical Review D, latest version
reflects changes from referee comment
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