1,390 research outputs found
Change in blood glucose level in rats after immobilization
Experiments were carried out on male white rats divided into four groups. In group one the blood glucose level was determined immediately after immobilization. In the other three groups, two hours following immobilization, the blood glucose level was determined every 20 minutes for 3 hours 40 minutes by the glucose oxidase method. Preliminary immobilization for 2 hours removed the increase in the blood glucose caused by the stress reaction. By the 2nd hour of immobilization in the presence of continuing stress, the blood glucose level stabilized and varied within 42 + or - 5.5 and 47 + or - 8.1 mg %. Within 2 hours after the immobilization, the differences in the blood glucose level of the rats from the control groups were statistically insignificant
Nuclear prolate-shape dominance with the Woods-Saxon potential
We study the prolate-shape predominance of the nuclear ground-state
deformation by calculating the masses of more than two thousand even-even
nuclei using the Strutinsky method, modified by Kruppa, and improved by us. The
influences of the surface thickness of the single-particle potentials, the
strength of the spin-orbit potential, and the pairing correlations are
investigated by varying the parameters of the Woods-Saxon potential and the
pairing interaction. The strong interference between the effects of the surface
thickness and the spin-orbit potential is confirmed to persist for six sets of
the Woods-Saxon potential parameters. The observed behavior of the ratios of
prolate, oblate, and spherical nuclei versus potential parameters are rather
different in different mass regions. It is also found that the ratio of
spherical nuclei increases for weakly bound unstable nuclei. Differences of the
results from the calculations with the Nilsson potential are described in
detail.Comment: 16 pages, 17 figure
Interstellar Sonic and Alfv\'enic Mach Numbers and the Tsallis Distribution
In an effort to characterize the Mach numbers of ISM magnetohydrodynamic
(MHD) turbulence, we study the probability distribution functions (PDFs) of
patial increments of density, velocity, and magnetic field for fourteen ideal
isothermal MHD simulations at resolution 512^3. In particular, we fit the PDFs
using the Tsallis function and study the dependency of fit parameters on the
compressibility and magnetization of the gas. We find that the Tsallis function
fits PDFs of MHD turbulence well, with fit parameters showing sensitivities to
the sonic and Alfven Mach numbers. For 3D density, column density, and
position-position-velocity (PPV) data we find that the amplitude and width of
the PDFs shows a dependency on the sonic Mach number. We also find the width of
the PDF is sensitive to global Alfvenic Mach number especially in cases where
the sonic number is high. These dependencies are also found for mock
observational cases, where cloud-like boundary conditions, smoothing, and noise
are introduced. The ability of Tsallis statistics to characterize sonic and
Alfvenic Mach numbers of simulated ISM turbulence point to it being a useful
tool in the analysis of the observed ISM, especially when used simultaneously
with other statistical techniques.Comment: 20 pages, 16 figures, ApJ submitte
Molecular structure of highly-excited resonant states in Mg and the corresponding Be+O and C+C decays
Exotic Be and C decays from high-lying resonances in Mg are
analyzed in terms of a cluster model. The calculated quantities agree well with
the corresponding experimental data. It is found that the calculated decay
widths are very sensitive to the angular momentum carried by the outgoing
cluster. It is shown that this property makes cluster decay a powerful tool to
determine the spin as well as the molecular structures of the resonances.Comment: 17 pages, no figur
Velocity Spectrum for HI at High Latitudes
In this paper we present the results of the statistical analysis of
high-latitude HI turbulence in the Milky Way. We have observed HI in the 21 cm
line, obtained with the Arecibo L-Band Feed Array (ALFA) receiver at the
Arecibo radio telescope. For recovering of velocity statistics we have used the
Velocity Coordinate Spectrum (VCS) technique. In our analysis we have used
direct fitting of the VCS model, as its asymptotic regimes are questionable for
Arecibo's resolution and given the restrictions from thermal smoothing of the
turbulent line. We have obtained a velocity spectral index , an
injection scale of pc, and an HI cold phase temperature of K. The spectral index is steeper than the Kolmogorov index and can be
interpreted as being due to shock-dominated turbulence.Comment: Accepted to Ap
Tsallis statistics as a tool for studying interstellar turbulence
We used magnetohydrodynamic (MHD) simulations of interstellar turbulence to
study the probability distribution functions (PDFs) of increments of density,
velocity, and magnetic field. We found that the PDFs are well described by a
Tsallis distribution, following the same general trends found in solar wind and
Electron MHD studies. We found that the PDFs of density are very different in
subsonic and supersonic turbulence. In order to extend this work to ISM
observations we studied maps of column density obtained from 3D MHD
simulations. From the column density maps we found the parameters that fit to
Tsallis distributions and demonstrated that these parameters vary with the
sonic and Alfv\'en Mach numbers of turbulence. This opens avenues for using
Tsallis distributions to study the dynamical and perhaps magnetic states of
interstellar gas.Comment: 8 pages, 5 figures, 1 table. Accepted for publication in the
Astrophysical Journa
Properties of Interstellar Turbulence from Gradients of Linear Radio Polarization Maps
Faraday rotation of linearly polarized radio signals provides a very
sensitive probe of fluctuations in the interstellar magnetic field and ionized
gas density resulting from magnetohydrodynamic (MHD) turbulence. We used a set
of statistical tools to analyze images of the spatial gradient of linearly
polarized radio emission () from the ISM for both
observational data from a test image of the Southern Galactic Plane Survey
(SGPS) and isothermal simulations of MHD turbulence. We compared the
observational data with results of synthetic observations obtained with the
simulations of 3D turbulence. Visually, in both data sets, a complex network of
filamentary structures is seen. Our analysis shows that the filaments in the
gradient can be produced by shocks as well as random fluctuations
characterizing the non-differentiable field of MHD turbulence. The latter
dominates for subsonic turbulence, while the former dominates for supersonic
turbulence. In order to quantitatively characterize these differences we use
the topology tool known as a genus curve as well as the moments of the image
distribution. We find that higher values for the moments correspond to cases of
with larger Mach numbers, but the strength of the
dependency is connected to the telescope angular resolution. In regards to the
topology, the supersonic filaments observed in have a
positive genus shift, which indicates a "swisscheese" like topology, while the
subsonic cases show a negative genus, indicating a "clump" like topology. In
the case of the genus, the dependency on the telescope resolution is not as
strong. The SGPS test region data has a distribution and morphology that
matches subsonic to transsonic type turbulence, which independently confirms
what is now expected for the WIM.Comment: Submitted to Ap
Hierarchical Structure of Magnetohydrodynamic Turbulence In Position-Position-Velocity Space
Magnetohydrodynamic turbulence is able to create hierarchical structures in
the interstellar medium that are correlated on a wide range of scales via the
energy cascade. We use hierarchical tree diagrams known as dendrograms to
characterize structures in synthetic Position-Position-Velocity (PPV) emission
cubes of optically thin isothermal magnetohydrodynamic turbulence. We show that
the structures and degree of hierarchy observed in PPV space are related to the
physics of the gas, i.e. self-gravity and the global sonic and Alfvenic Mach
number. Simulations with higher Alfvenic Mach number, self-gravity and
supersonic flows display enhanced hierarchical structure. We observed a strong
sonic and Alfvenic dependency when we apply the the statistical moments (i.e.
mean, variance, skewness, kurtosis) to the dendrogram distribution. Larger
magnetic field and sonic Mach number correspond to larger values of the
moments. Application of the dendrogram to 3D density cubes, also known as
Position-Position-Position cubes (PPP), reveals that the dominant emission
contours in PPP and PPV are related for supersonic gas but not for subsonic. We
also explore the effects of smoothing, thermal broadening and velocity
resolution on the dendrograms in order to make our study more applicable to
observational data. These results all point to hierarchical tree diagrams as
being a promising additional tool for studying ISM turbulence and star forming
regions in the direction of obtaining information on the degree of
self-gravity, the Mach numbers and the complicated relationship between PPV and
PPP.Comment: submitted to Ap
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