Population structure of Pacific yellowfin tuna

ENGLISH: The population structure and production of Pacific yellowfin tuna, Thunnus albacares, were examined by studying most of the basic data available on stock assessment, as well as other data, for the period 1965 to 1972. The data were obtained mainly from the Japanese longline fishery in the Pacific Ocean east of about 1200E and from the purse-seine fishery in the eastern Pacific east of about 140oW. Data from genetic studies of subpopulations were not used due to their preliminary nature. It was concluded that the concept of "semi-independent" subpopulations proposed by Kamimura and Honma (1963) and Royce (1964) defines the population structure of Pacific yellowfin. At least three stocks (i.e. western, central and eastern), relatively independent of each other, are thought to exist, but the actual number and location of subpopulations is still unclear. Possible north-south separations, indicated to some extent by genetic studies and tagging, could be neither substantiated nor rejected on the basis of this study. Finally, unless some major change in the fishing technology occurs, it is doubtful if any significant sustainable increase in yellowfin production from the Pacific is possible. The greatest potential for increase, if any, appears to be based on changing the size structure of yellowfin in the catch from the central Pacific. SPANISH: Se examino la estructura de la población y la producción del atún aleta amarilla del Pacifico Thunnus albacares para estudiar la mayoría de los datos básicos que se tenían sobre el avalúo de la población, como también otra información correspondiente al periodo de 1965·1972. Los datos fueron obtenidos principalmente de las pescas palangreros japonesas del Océano Pacifico al este de los 1200 E y de las pescas con redes de cerco del Pacifico oriental, al este de los 140oW. No se emplearon los datos de estudios genéticos de las subpoblaciones porque eran mas bien preliminares. Se concluyo que el concepto propuesto por Kamimura y Honma (1963) y Royce (1964) de subpoblaciones "semiindependientes" define la estructura de la población del aleta amarilla en el Pacifico. Se cree que existen por 10 menos tres existencias (e.d. la occidental, central y oriental), relativamente independientes la una de la otra, pero no se conoce con certeza cuantas subpoblaciones hay y donde se encuentran. La posible separación norte-sur, indicada, hasta cierto punto, por los análisis genéticos y del marcado, no puede ni confirmarse ni rechazarse basados en este estudio. Finalmente, a no ser que ocurra algún gran cambio en la tecnología pesquera es dudoso que sea posible obtener un aumento constante e importante en la producción del aleta amarilla del Pacifico. El potencial mayor de aumento, si es que existe alguno, parece que se basa en el cambio de la estructura de talla en la captura del aleta amarilla del Pacifico central. (PDF contains 169 pages.

Finding Exponential Product Formulas of Higher Orders

In the present article, we review a continual effort on generalization of the Trotter formula to higher-order exponential product formulas. The exponential product formula is a good and useful approximant, particularly because it conserves important symmetries of the system dynamics. We focuse on two algorithms of constructing higher-order exponential product formulas. The first is the fractal decomposition, where we construct higher-order formulas recursively. The second is to make use of the quantum analysis, where we compute higher-order correction terms directly. As interludes, we also have described the decomposition of symplectic integrators, the approximation of time-ordered exponentials, and the perturbational composition.Comment: 22 pages, 9 figures. To be published in the conference proceedings ''Quantum Annealing and Other Optimization Methods," eds. B.K.Chakrabarti and A.Das (Springer, Heidelberg

A generalization of heterochromatic graphs

In 2006, Suzuki, and Akbari & Alipour independently presented a necessary and sufficient condition for edge-colored graphs to have a heterochromatic spanning tree, where a heterochromatic spanning tree is a spanning tree whose edges have distinct colors. In this paper, we propose $f$-chromatic graphs as a generalization of heterochromatic graphs. An edge-colored graph is $f$-chromatic if each color $c$ appears on at most $f(c)$ edges. We also present a necessary and sufficient condition for edge-colored graphs to have an $f$-chromatic spanning forest with exactly $m$ components. Moreover, using this criterion, we show that a $g$-chromatic graph $G$ of order $n$ with $|E(G)|>\binom{n-m}{2}$ has an $f$-chromatic spanning forest with exactly $m$ ($1 \le m \le n-1$) components if $g(c) \le \frac{|E(G)|}{n-m}f(c)$ for any color $c$.Comment: 14 pages, 4 figure

Nonlinear integral equations for thermodynamics of the sl(r+1) Uimin-Sutherland model

We derive traditional thermodynamic Bethe ansatz (TBA) equations for the sl(r+1) Uimin-Sutherland model from the T-system of the quantum transfer matrix. These TBA equations are identical to the ones from the string hypothesis. Next we derive a new family of nonlinear integral equations (NLIE). In particular, a subset of these NLIE forms a system of NLIE which contains only a finite number of unknown functions. For r=1, this subset of NLIE reduces to Takahashi's NLIE for the XXX spin chain. A relation between the traditional TBA equations and our new NLIE is clarified. Based on our new NLIE, we also calculate the high temperature expansion of the free energy.Comment: 24 pages, 4 figures, to appear in J. Phys. A: Math. Ge

Critical exponents of the two-layer Ising model

The symmetric two-layer Ising model (TLIM) is studied by the corner transfer matrix renormalisation group method. The critical points and critical exponents are calculated. It is found that the TLIM belongs to the same universality class as the Ising model. The shift exponent is calculated to be 1.773, which is consistent with the theoretical prediction 1.75 with 1.3% deviation.Comment: 7 pages, with 10 figures include

From the quantum Jacobi-Trudi and Giambelli formula to a nonlinear integral equation for thermodynamics of the higher spin Heisenberg model

We propose a nonlinear integral equation (NLIE) with only one unknown function, which gives the free energy of the integrable one dimensional Heisenberg model with arbitrary spin. In deriving the NLIE, the quantum Jacobi-Trudi and Giambelli formula (Bazhanov-Reshetikhin formula), which gives the solution of the T-system, plays an important role. In addition, we also calculate the high temperature expansion of the specific heat and the magnetic susceptibility.Comment: 18 pages, LaTeX; some explanations, 2 figures, one reference added; typos corrected; to appear in J. Phys. A: Math. Ge

Multiplicity dependence of identical particle correlations in the quantum optical approach

Identical particle correlations at fixed multiplicity are consideres in the presence of chaotic and coherent fields. The multiplicity distribution, one-particle momentum density, and two-particle correlation function are obtained based on the diagrammatic representation for cmulants in semi-inclusive events. Our formulation is applied to the analysis of the experimental data on the multiplicity dependence of correlation functions reported by the UA1 and the OPAL Collaborations.Comment: 14 pages, 7 figure