46 research outputs found
Advantage of Animal Models with Metabolic Flexibility for Space Research Beyond Low Earth Orbit
As the worlds space agencies and commercial entities continue to expand beyond Low Earth Orbit (LEO), novel approaches to carry out biomedical experiments with animals are required to address the challenge of adaptation to space flight and new planetary environments. The extended time and distance of space travel along with reduced involvement of Earth-based mission support increases the cumulative impact of the risks encountered in space. To respond to these challenges, it becomes increasingly important to develop the capability to manage an organisms self-regulatory control system, which would enable survival in extraterrestrial environments. To significantly reduce the risk to animals on future long duration space missions, we propose the use of metabolically flexible animal models as pathfinders, which are capable of tolerating the environmental extremes exhibited in spaceflight, including altered gravity, exposure to space radiation, chemically reactive planetary environments and temperature extremes.In this report we survey several of the pivotal metabolic flexibility studies and discuss the importance of utilizing animal models with metabolic flexibility with particular attention given to the ability to suppress the organism's metabolism in spaceflight experiments beyond LEO. The presented analysis demonstrates the adjuvant benefits of these factors to minimize damage caused by exposure to spaceflight and extreme planetary environments. Examples of microorganisms and animal models with dormancy capabilities suitable for space research are considered in the context of their survivability under hostile or deadly environments outside of Earth. Potential steps toward implementation of metabolic control technology in spaceflight architecture and its benefits for animal experiments and manned space exploration missions are discussed
Deformed Harmonic Oscillators for Metal Clusters: Analytic Properties and Supershells
The analytic properties of Nilsson's Modified Oscillator (MO), which was
first introduced in nuclear structure, and of the recently introduced, based on
quantum algebraic techniques, 3-dimensional q-deformed harmonic oscillator
(3-dim q-HO) with Uq(3) > SOq(3) symmetry, which is known to reproduce
correctly in terms of only one parameter the magic numbers of alkali clusters
up to 1500 (the expected limit of validity for theories based on the filling of
electronic shells), are considered. Exact expressions for the total energy of
closed shells are determined and compared among them. Furthermore, the
systematics of the appearance of supershells in the spectra of the two
oscillators is considered, showing that the 3-dim q-HO correctly predicts the
first supershell closure in alkali clusters without use of any extra parameter.Comment: 25 pages LaTeX plus 21 postscript figure
CraniologiCal CharaCteristiCs of wild boars from the region of sarnena sredna gora mountain, bulgaria
abstract Doychev, v., Е. Raychev and D. KostoV, 2012. craniological characteristics of wild boars from the region of sarnena sredna Gora Mountain, Bulgaria. Bulg. J. Agric. Sci., craniological analysis of 18 male wild boar skulls has been conducted at completed growth (fully-grown third molar tooth). 44 craniological measurements have been made characterizing both the basic skull shapes and proportions (length, height, width and profile line), and the shape and proportions of the various skull parts (facial and cerebral) and of the various bones (lacrimal, palatal, etc.). the values found have been compared to the ones obtained by other authors. Based on the values found a classification analysis has been made to establish the population appurtenance of wild boars inhabiting in the region of sarnena sredna Gora Mountain. It has been found out that male boars from the region of sarnena sredna Gora Mountain have an extended, relatively narrow and low skull, with a straight profile line. The lacrimal bone is extended, with a trapezoid shape. concerning their craniological characteristics, male wild boars from the region of sarnena sredna Gora Mountain are attributed to the wild boar population inhabiting North Bulgaria. the basic skull dimensions characterizing its length, height and width are in positive correlation
Sequence of Potentials Interpolating between the U(5) and E(5) Symmetries
It is proved that the potentials of the form (with being
integer) provide a ``bridge'' between the U(5) symmetry of the Bohr Hamiltonian
with a harmonic oscillator potential (occuring for ) and the E(5) model of
Iachello (Bohr Hamiltonian with an infinite well potential, materialized for
infinite ). Parameter-free (up to overall scale factors) predictions for
spectra and B(E2) transition rates are given for the potentials ,
, , corresponding to ratios of 2.093, 2.135,
2.157 respectively, compared to the ratios 2.000 of U(5) and 2.199 of
E(5). Hints about nuclei showing this behaviour, as well as about potentials
``bridging'' the E(5) symmetry with O(6) are briefly discussed. A note about
the appearance of Bessel functions in the framework of E(n) symmetries is given
as a by-product.Comment: LaTeX, 17 pages, 9 postscript figure
Six-dimensional Davidson potential as a dynamical symmetry of the symplectic Interacting Vector Boson Model
A six-dimensional Davidson potential, introduced within the framework of the
Interacting Vector Boson Model (IVBM), is used to describe nuclei that exhibit
transitional spectra between the purely rotational and vibrational limits of
the theory. The results are shown to relate to a new dynamical symmetry that
starts with the reduction. Exact
solutions for the eigenstates of the model Hamiltonian in the basis defined by
a convenient subgroup chain of SO(6) are obtained. A comparison of the
theoretical results with experimental data for heavy nuclei with transitional
spectra illustrates the applicability of the theory.Comment: 9 pages, 4 figure
q-Analogue of
A natural embedding for the
corresponding quantum algebras is constructed through the appropriate
comultiplication on the generators of each of the and
algebras. The above embedding is proved in their -boson realization by means
of the isomorphism between the (mn)(m)(n) algebras.Comment: 11 pages, no figures. In memory of professor R. P. Rousse
In memoriam two distinguished participants of the Bregenz Symmetries in Science Symposia: Marcos Moshinsky and Yurii Fedorovich Smirnov
Some particular facets of the numerous works by Marcos Moshinsky and Yurii
Fedorovich Smirnov are presented in these notes. The accent is put on some of
the common interests of Yurii and Marcos in physics, theoretical chemistry, and
mathematical physics. These notes also contain some more personal memories of
Yurii Smirnov.Comment: Submitted for publication in Journal of Physics: Conference Serie
Remarcs on the shape transition from spherical to deformed gamma unstable nuclei
Energies and transition probabilities for low lying states in Ba and
^{104Ru were calculated within a hybrid model.The ground and the first
states are described alternatively as a harmonic and anharmonic vibrator states
while the remaining states as states with E(5) symmetry. One concludes that a
gradual setting of the 'critical' potential yields a better agreement with the
experimental data. Very good agreement with the data is obtained for
Ru. Comparing the present results with those of E(5) symmetry, it is
conspicuous that the present formalism add corrections to the E(5) formalism by
bringing the predictions closer to the experimental data. Analytical
relationship between the states with U(5) symmetry and those given by the E(5)
description is established.Comment: 21 pages, 3 figures, submitted for publicatio
Unified description of magic numbers of metal clusters in terms of the 3-dimensional q-deformed harmonic oscillator
Magic numbers predicted by a 3-dimensional q-deformed harmonic oscillator
with Uq(3)>SOq(3) symmetry are compared to experimental data for atomic
clusters of alkali metals (Li, Na, K, Rb, Cs), noble metals (Cu, Ag, Au),
divalent metals (Zn, Cd), and trivalent metals (Al, In), as well as to
theoretical predictions of jellium models, Woods-Saxon and wine bottle
potentials, and to the classification scheme using the 3n+l pseudo quantum
number. In alkali metal clusters and noble metal clusters the 3-dimensional
q-deformed harmonic oscillator correctly predicts all experimentally observed
magic numbers up to 1500 (which is the expected limit of validity for theories
based on the filling of electronic shells), while in addition it gives
satisfactory results for the magic numbers of clusters of divalent metals and
trivalent metals, thus indicating that Uq(3), which is a nonlinear extension of
the U(3) symmetry of the spherical (3-dimensional isotropic) harmonic
oscillator, is a good candidate for being the symmetry of systems of several
metal clusters. The Taylor expansions of angular momentum dependent potentials
approximately producing the same spectrum as the 3-dimensional q-deformed
harmonic oscillator are found to be similar to the Taylor expansions of the
symmetrized Woods-Saxon and wine-bottle symmetrized Woods-Saxon potentials,
which are known to provide successful fits of the Ekardt potentials.Comment: 23 pages including 7 table
and bifurcations in rotational bands of diatomic molecules
It is shown that the recently observed bifurcation seen in
superdeformed nuclear bands is also occurring in rotational bands of diatomic
molecules. In addition, signs of a bifurcation, of the same order
of magnitude as the one, are observed both in superdeformed
nuclear bands and rotational bands of diatomic molecules.Comment: LaTex twice, 10 pages and 5 PS figures provided upon demand by the
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