5,048 research outputs found
Contributions to the biology of the panga Pterogymnus laniarus (Pisces : Sparidae): age, growth and reproduction
All the fish used in this investigation were caught by commercial side trawlers along the eastern Cape coast of South Africa. Age and growth of P. laniarius was determined from otoliths collected monthly from April 1974 to September 1975. The validity of annuli was proved by monthly edge examination of the otoliths. There is no difference in growth between the sexes. The Von Bertalanffy equation Lt = 48,1 (l-e-0,10(e + 0.22)) was found to describe the growth of the panga in length. Some fish become sexually mature at a total length of 26 cm. Fifty percent maturity is attained at a length of 28 cm, between the ages of 4 and 5 years. All fish are sexually mature at a total length of 32 cm, at an age of 6 years. The spawning season of the panga extends from mid-September to May
Branching rules for the subgroups of the unitary group
Expressions are given in terms of simple matrices d for the reduction of the Kronecker (outer) product of two or more irreducible representations which can be characterized by Young patterns. These are then used to obtain practical formulas for branching rules. The needed matrices d can be constructed by a very efficient recursive process.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69691/2/JMAPAQ-19-3-720-1.pd
Construction of SU(3) irreps in canonical SO(3)-coupled bases
Alternative canonical methods for defining canonical SO(3)-coupled bases for
SU(3) irreps are considered and compared. It is shown that a basis that
diagonalizes a particular linear combination of SO(3) invariants in the SU(3)
universal enveloping algebra gives basis states that have good quantum
numbers in the asymptotic rotor-model limit.Comment: no figure
The Gaussian formula and spherical aberration of the static and moving curved mirrors from Fermat's principle
The Gaussian formula and spherical aberrations of the static and relativistic
curved mirrors are analyzed using the optical path length (OPL) and Fermat's
principle. The geometrical figures generated by the rotation of conic sections
about their symmetry axes are considered for the shapes of the mirrors. By
comparing the results in static and relativistic cases, it is shown that the
focal lengths and the spherical aberration relations of the relativistic
mirrors obey the Lorentz contraction. Further analysis of the spherical
aberrations for both static and relativistic cases have resulted in the
information about the limits for the paraxial approximation, as well as for the
minimum speed of the systems to reduce the spherical aberrations.Comment: 15 pages, 7 figures, uses iopart. Major revisions on the physical
interpretations of the results. Accepted for publication in J. Op
Representation of the fiveâdimensional harmonic oscillator with scalarâvalued U(5) â SO(5) â SO(3)âcoupled VCS wave functions
Vector coherent state methods, which reduce the U(5) â SO(5) â SO(3) subgroup chain, are used to construct basis states for the fiveâdimensional harmonic oscillator. Algorithms are given to calculate matrix elements in this basis. The essential step is the construction of SO(5) â SO(3) irreps of type [v,0]. The methodology is similar to that used in two recent papers except that oneâdimensional, as opposed to multidimensional, vectorâvalued wave functions are used to give conceptually simpler results. Another significant advance is a canonical resolution of the SO(5) â SO(3) multiplicity problem. © 1995 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70418/2/JMAPAQ-36-9-4711-1.pd
Phenomenology of the Baryon Resonance 70-plet at Large N_c
We examine the multiplet structure and decay channels of baryon resonances in
the large N_c QCD generalization of the N_c = 3 SU(6) spin-flavor 70. We show
that this ``70'', while a construct of large N_c quark models, actually
consists of five model-independent irreducible spin-flavor multiplets in the
large N_c limit. The preferred decay modes for these resonances fundamentally
depend upon which of the five multiplets to which the resonance belongs. For
example, there exists an SU(3) ``8'' of resonances that is eta-philic and
pi-phobic, and an ``8'' that is the reverse. Moreover, resonances with a strong
SU(3) ``1'' component prefer to decay via a K-bar rather than via a pi.
Remarkably, available data appears to bear out these conclusions.Comment: 26 pages, ReVTe
Vector coherent state theory of the generic representations of so(5) in an so(3) basis
For applications of group theory in quantum mechanics, one generally needs
explicit matrix representations of the spectrum generating algebras that arise
in bases that reduce the symmetry group of some Hamiltonian of interest. Here
we use vector coherent state techniques to develop an algorithm for
constructing the matrices for arbitrary finite-dimensional irreps of the SO(5)
Lie algebra in an SO(3) basis. The SO(3) subgroup of SO(5) is defined by
regarding SO(5) as linear transformations of the five-dimensional space of an
SO(3) irrep of angular momentum two. A need for such irreps arises in the
nuclear collective model of quadrupole vibrations and rotations. The algorithm
has been implemented in MAPLE, and some tables of results are presented.Comment: 20 pages, uses multirow.sty, submitted to J. Math. Phy
Occupation probability of harmonic-oscillator quanta for microscopic cluster-model wave functions
We present a new and simple method of calculating the occupation probability
of the number of total harmonic-oscillator quanta for a microscopic
cluster-model wave function. Examples of applications are given to the recent
calculations including -model for He, -model for
Li, and -model for Be as well as the classical
calculations of -model for Li and -model
for C. The analysis is found to be useful for quantifying the amount of
excitations across the major shell as well as the degree of clustering. The
origin of the antistretching effect is discussed.Comment: 9 page
Mass and Spin of Poincare Gauge Theory
We discuss two expressions for the conserved quantities (energy momentum and
angular momentum) of the Poincar\'e Gauge Theory. We show, that the variations
of the Hamiltonians, of which the expressions are the respective boundary
terms, are well defined, if we choose an appropriate phase space for asymptotic
flat gravitating systems. Furthermore, we compare the expressions with others,
known from the literature.Comment: 16 pages, plain-tex; to be published in Gen. Rel. Gra
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