276 research outputs found
3D Coronal Density Reconstruction and Retrieving the Magnetic Field Structure during Solar Minimum
Measurement of the coronal magnetic field is a crucial ingredient in
understanding the nature of solar coronal phenomena at all scales. We employed
STEREO/COR1 data obtained during a deep minimum of solar activity in February
2008 (Carrington rotation CR 2066) to retrieve and analyze the
three-dimensional (3D) coronal electron density in the range of heights from
1.5 to 4 Rsun using a tomography method. With this, we qualitatively deduced
structures of the coronal magnetic field. The 3D electron density analysis is
complemented by the 3D STEREO/EUVI emissivity in the 195 A band obtained by
tomography for the same CR. A global 3D MHD model of the solar corona was used
to relate the reconstructed 3D density and emissivity to open/closed magnetic
field structures. We show that the density maximum locations can serve as an
indicator of current sheet position, while the locations of the density
gradient maximum can be a reliable indicator of coronal hole boundaries. We
find that the magnetic field configuration during CR 2066 has a tendency to
become radially open at heliocentric distances greater than 2.5 Rsun. We also
find that the potential field model with a fixed source surface (PFSS) is
inconsistent with the boundaries between the regions with open and closed
magnetic field structures. This indicates that the assumption of the potential
nature of the coronal global magnetic field is not satisfied even during the
deep solar minimum. Results of our 3D density reconstruction will help to
constrain solar coronal field models and test the accuracy of the magnetic
field approximations for coronal modeling.Comment: Published in "Solar Physics
NN potentials from inverse scattering in the J-matrix approach
An approximate inverse scattering method [7,8] has been used to construct
separable potentials with the Laguerre form factors. As an application, we
invert the phase shifts of proton-proton in the and
channels and neutron-proton in the channel elastic scattering. In
the latter case the deuteron wave function of a realistic potential was
used as input.Comment: LaTex2e, 17 pages, 3 Postscript figures; corrected typo
Peroxisomes in intestinal and gallbladder epithelial cells of the stickleback, Gasterosteus aculeatus L. (Teleostei)
The occurrence of microbodies in the epithelial cells of the intestine and gallbladder of the stickleback, Gasterosteus aculeatus L., is described. In the intestine the organelles are predominantly located in the apical and perinuclear zone of the cells and may contain small crystalline cores. In gallbladder epithelial cells the microbodies are distributed randomly. The latter organdies are characterized by the presence of large crystalloids. Cytochemical and biochemical experiments show that catalase and D-amino acid oxidase are main matrix components of the microbodies in both the intestinal and gallbladder epithelia. These organelles therefore are considered peroxisomes. In addition, in intestinal mucosa but not in gallbladder epithelium a low activity of palmitoyl CoA oxidase was detected biochemically. Urate oxidase and L-α hydroxy acid oxidase activities could not be demonstrated.
Chaos in Static Axisymmetric Spacetimes I : Vacuum Case
We study the motion of test particle in static axisymmetric vacuum spacetimes
and discuss two criteria for strong chaos to occur: (1) a local instability
measured by the Weyl curvature, and (2) a tangle of a homoclinic orbit, which
is closely related to an unstable periodic orbit in general relativity. We
analyze several static axisymmetric spacetimes and find that the first
criterion is a sufficient condition for chaos, at least qualitatively. Although
some test particles which do not satisfy the first criterion show chaotic
behavior in some spacetimes, these can be accounted for the second criterion.Comment: More comments for the quantitative estimation of chaos are added, and
some inappropriate terms are changed. This will appear on Class. Quant. Gra
TomograPy: A Fast, Instrument-Independent, Solar Tomography Software
Solar tomography has progressed rapidly in recent years thanks to the
development of robust algorithms and the availability of more powerful
computers. It can today provide crucial insights in solving issues related to
the line-of-sight integration present in the data of solar imagers and
coronagraphs. However, there remain challenges such as the increase of the
available volume of data, the handling of the temporal evolution of the
observed structures, and the heterogeneity of the data in multi-spacecraft
studies.
We present a generic software package that can perform fast tomographic
inversions that scales linearly with the number of measurements, linearly with
the length of the reconstruction cube (and not the number of voxels) and
linearly with the number of cores and can use data from different sources and
with a variety of physical models: TomograPy
(http://nbarbey.github.com/TomograPy/), an open-source software freely
available on the Python Package Index. For performance, TomograPy uses a
parallelized-projection algorithm. It relies on the World Coordinate System
standard to manage various data sources. A variety of inversion algorithms are
provided to perform the tomographic-map estimation. A test suite is provided
along with the code to ensure software quality. Since it makes use of the
Siddon algorithm it is restricted to rectangular parallelepiped voxels but the
spherical geometry of the corona can be handled through proper use of priors.
We describe the main features of the code and show three practical examples
of multi-spacecraft tomographic inversions using STEREO/EUVI and STEREO/COR1
data. Static and smoothly varying temporal evolution models are presented.Comment: 21 pages, 6 figures, 5 table
ПОРУШЕННЯ КИСНЕВОГО ЗАБЕЗПЕЧЕННЯ ПЕРИФЕРІЙНИХ ТКАНИН ПРИ АНЕМІЇ ХРОНІЧНИХ ЗАХВОРЮВАНЬ
The article evaluated the indexes of oxygenation of arterial and venous blood in 37 patients with chronic heart failure and anaemia. The expediency of applications the definitions of indexes oxygenation of arterial and venous blood in this patients was exhausted.В статье приведена оценка показателей оксигенации артериальной и венозной крови у 37 больных с хронической сердечной недостаточностью и анемией. Обоснована целесообразность определения параметров оксигенации артериальной и венозной крови у данной категории больных.У статті наведено оцінку показників оксигенації артеріальної і венозної крові у 37 хворих на хронічну серцеву недостатність та анемію. Обгрунтовано доцільність визначення параметрів оксигенації артеріальної і венозної крові у даної категорії хворих
Cyclic shear tests on RC precast beam-to-column connections retrofitted with a three-hinged steel device
Recent European earthquakes demonstrated that the seismic response of RC precast structures can be significantly influenced by the connection systems. Moreover, during past seismic events, many failures of the beam-to-column connections occurred due to their inadequate strength under seismic loads. The seismic safety of these connections has a crucial role in the overall seismic capacity of existing precast structures.
A new connection system is employed as a retrofitting solution for a damaged beam-to-column connection and its cyclic shear performance is investigated by means of two cyclic shear tests on two different configurations. In both the experimental tests, the results demonstrate an efficient behavior of the retrofitted connections under horizontal cyclic loads. The comparison between the performance of the investigated connection and the response of a typical beam-to-column dowel connection allows to discuss the main critical features of the dowel connection system
Immunohistochemical evaluation of surfactant-associated protein in fibrosis-cavernous pulmonary tuberculosis
Background. Despite the progress and development of scientific directions in various fields of medicine, the problem of tuberculosis and its morphological manifestations remains relevant and is not fully disclosed due to complex pathogenesis, the presence of various clinical forms, therapeutic pathomorphosis, torpid to therapy, the presence of relapses. It is known that a surfactant system occupies a special place in the system of local lung protection.Aim. To study the condition of surfactant-assotiated protein A in the foci of specific destruction and in the surrounding intact lung tissue to assess its functional status, degree of respiratory failure and possible dissemination of tuberculous inflammation.Material and Metods. An analysis of 163 lung fragments of the dead or operated on for cavernous pulmonary tuberculosis with active bacterial excretion of 89 fragments and with clinical abacilation – 74 was carried out. Results. A morphological study revealed stereotypical dynamic depression of surfactant-associated protein A in all the samples studied, both in the areas of cavernous destruction and pericavernouse zone, and in intact lung tissue. The maximum intensivity of the immunohistochemical expression of this surfactant protein was recorded in the alveolar macrophages, which indicated intensive recycling and utilization of the components of the surfactant.Conclusion. Minimizing the production of surfactant components and its active utilization in intact lung tissue leads to a collapse of the alveoli with subsequent progression of respiratory failure
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