344 research outputs found
Note on Moufang-Noether currents
The derivative Noether currents generated by continuous Moufang
tranformations are constructed and their equal-time commutators are found. The
corresponding charge algebra turns out to be a birepresentation of the tangent
Mal'ltsev algebra of an analytic Moufang loop.Comment: LaTeX2e, 6 pages, no figures, presented on "The XVth International
Colloquium on Integrable Systems and Quantum Symmetries, Prague, 15-17 June,
2006
Crescimento da pescada-foguete (Macrodon ancylodon): aspecto quantitativo
We determined the age of the commercial marine fish "pescada-foguete" (Macrodon ancylodon, Bloch 1801) caught by trawls along the southern coast of Brazil (28ºS-34ºS), from 1961 to 1963, by means of the annuli in otoliths (CHUGUNOVA, 1959). We correlated the mean total length (L) in centimetres with the age (t) in years by means of the BERTALANFFY expression adjusted by FORD-WALFORD method (BEVERTON & HOLT, 1957). The mean total length was correlated with the mean weight (W) in grams, by means of the expression W = aLb adjusted by least square method, after a logarithmic transformation. Results
Migração da pescada-foguete, Macrodon ancylodon
The "pescada-foguete" fish presented (1961-1964) migration along the southern coast of Brazil (from 28ºS to 34ºS), according to the following expression, adjusted by the least squares method: y = 30.2 + 1.7 cos 30 (x - 1.5) where: y - latitude with maximum production per unit effort (ºS) X = 1, % .... 12, months of the yea
Análise da pesca da pescada-foguete na costa centro-sul do Brasil
In this paper data on catch and effort by gear are analysed, for weakfish (Macrodon ancylodon) landed at Santos from January 1959 to December 1963. The region studied was a narrow band about 30 nautical miles wide, along the southern coast of Brazil, between 23º S and 34º S. From the analysis of monthly data of production per unit-effort by squares of 1º on a side, we divided the studied region in two areas: area I (from 23º S to 27º S) and area II (from 28º S to 34º S). The index of unit-effort production and the effort concentration index were computed grouping the data by quarters. From the results we may drow the following conclusions: 1 - In a general way, the effort for catch weak-fish has been applied satisfactorily because the medium and large parejas have operated almost in areas with average density on¹ higher than average density; 2 - The production per unit-effort in the area I is smaller than the production in area II, which suggests that the index of abundance is higher in area II; 3 - The decrease in production per unit-effort, in area II, suggests a decrease in the abundance or availability of weak-fish in this area; 4 - In the area I, the index of production per unit-effort remained approximately at the same level
Helminth parasites of the oceanic horse mackerel Trachurus picturatus Bowdich 1825 (Pisces: Carangidae) from Madeira Island, Atlantic Ocean, Portugal
The helminth parasite fauna of the oceanic horse mackerel Trachurus picturatus Bowdich 1825, caught off the Madeira Islands was composed of six different taxa. Prevalence and abundance of larval Anisakis sp. (Nematoda: Anisakidae) and Nybelinia lingualis (Trypanorhyncha: Tentaculariidae), the most common parasite taxa, were 24.3%, 0.9 and 37.9%, 0.7, respectively. Bolbosoma vasculosum (Acanthocephala: Polymorphidae) and the monogeneans Heteraxinoides atlanticus (Monogenea: Heteraxinidae) and Pseudaxine trachuri (Monogenea: Gastrocotylidae) were comparatively rare. The depauperate helminth fauna of the oceanic horse mackerel at Madeira compared to other geographical regions of the north-eastern Atlantic, namely the Azores banks and the West African coast, may be attributed to the paucity of nutrients off oceanic islands and to a low density of the fish population.This work was partially supported by the Portuguese
Foundation for Science and Technology (FCT) Pluriannual
Programs.info:eu-repo/semantics/publishedVersio
Fractalization of Torus Revisited as a Strange Nonchaotic Attractor
Fractalization of torus and its transition to chaos in a quasi-periodically
forced logistic map is re-investigated in relation with a strange nonchaotic
attractor, with the aid of functional equation for the invariant curve.
Existence of fractal torus in an interval in parameter space is confirmed by
the length and the number of extrema of the torus attractor, as well as the
Fourier mode analysis. Mechanisms of the onset of fractal torus and the
transition to chaos are studied in connection with the intermittency.Comment: Latex file ( figures will be sent electronically upon
request):submitted to Phys.Rev. E (1996
Multifractal Scaling, Geometrical Diversity, and Hierarchical Structure in the Cool Interstellar Medium
Multifractal scaling (MFS) refers to structures that can be described as a
collection of interwoven fractal subsets which exhibit power-law spatial
scaling behavior with a range of scaling exponents (concentration, or
singularity, strengths) and dimensions. The existence of MFS implies an
underlying multiplicative (or hierarchical, or cascade) process. Panoramic
column density images of several nearby star- forming cloud complexes,
constructed from IRAS data and justified in an appendix, are shown to exhibit
such multifractal scaling, which we interpret as indirect but quantitative
evidence for nested hierarchical structure. The relation between the dimensions
of the subsets and their concentration strengths (the "multifractal spectrum'')
appears to satisfactorily order the observed regions in terms of the mixture of
geometries present: strong point-like concentrations, line- like filaments or
fronts, and space-filling diffuse structures. This multifractal spectrum is a
global property of the regions studied, and does not rely on any operational
definition of "clouds.'' The range of forms of the multifractal spectrum among
the regions studied implies that the column density structures do not form a
universality class, in contrast to indications for velocity and passive scalar
fields in incompressible turbulence, providing another indication that the
physics of highly compressible interstellar gas dynamics differs fundamentally
from incompressible turbulence. (Abstract truncated)Comment: 27 pages, (LaTeX), 13 figures, 1 table, submitted to Astrophysical
Journa
Site adaptations of Acanthogyrus (Acanthosentis) tilapiae: Observations through light and scanning electron microscopy
Acanthogyrus (Acanthosentis) tilapiae parasites were collected from the intestines of 300 fish belonging to three tilapia species sourced at the River Nile, Giza, Egypt. The proboscis of the parasite was characterized by three rows of hooks that curved towards the posterior of the body. The first row is supported by unmodified hooks. The parasite tegument has a series of alternative folds and a large number of pores. Sensory ganglia are located on the surface of the proboscis and body. Acanthogyrus (Acanthosentis) tilapiae provokes an aggressive host response indicated by hyperplasia of the intestinal goblet cells and focal eosinophil infiltrations. This acanthocephalan parasite shows a highly modified adaptation to its site of host infection
On Deformations of n-Lie algebras
The aim of this paper is to review the deformation theory of -Lie
algebras. We summarize the 1-parameter formal deformation theory and provide a
generalized approach using any unital commutative associative algebra as a
deformation base. Moreover, we discuss degenerations and quantization of
-Lie algebras.Comment: Proceeding of the conference Dakar's Workshop in honor of Pr Amin
Kaidi. arXiv admin note: text overlap with arXiv:hep-th/9602016 by other
author
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