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

On Deformations of n-Lie algebras

The aim of this paper is to review the deformation theory of $n$-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 $n$-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

Spiral valve parasites of blue and common thresher sharks as indicators of shark feeding behaviour and ecology

Open Access via the Jisc Wiley agreement Acknowledgements This work would not have been possible without the assistance and samples provided by the National Marine Fisheries Service (NMFS) Southwest Region Fishery Observer Program and the participating drift gillnet fishermen. A. Arevalo, E. Reed, H. Colley, J. Williams, J. Tamez and K. Tran assisted with spiral valve dissections and parasite sorting in the lab. D. Losey helped with library research. D. Sweetnam, A. Yau, A. Thompson, M. Craig, S. Stohs, G. DiNardo provided constructive critiques that helped improve the manuscript. This research was supported by the National Oceanographic Atmospheric Administration (NOAA).Peer reviewedPublisher PD

Antimicrobial, Cytotoxic and Antioxidant Activities and Determination of the Total Tannin Content of Bark Extracts Endopleura uchi

Endopleura uchi is a typical Amazonian tree and its bark is popularly employed in the preparation of teas against myomas, arthritis, influenza, diarrhea and cancer. In this study, the antioxidant activity, cytotoxicity and antimicrobial activity of five different extracts of the bark, selected by their total tannin content, were assessed. The potential antioxidant activity of the extracts was determined by 2.2-diphenyl-1-picrylhydrazyl radical scavenging assay and the values found were very similar among the extracts and to the standards antioxidants used in the tests. Cytotoxicity analysis in mammalian cells indicated that all the tested extracts exhibited IC50 values higher than the highest concentration used, showing that they do not present a risk when consumed under these conditions. Extract tested against five bacterial strains and one yeast strain did not show satisfactory growth inhibitory activity, and even the extracts that showed some antimicrobial activity were not effective at any dilution to determine the minimum inhibitory concentration. The results may serve as a reference for subsequent works, since such reference values described in the literature for the bark of E. uchi

Observation of Live Ticks (Haemaphysalis flava) by Scanning Electron Microscopy under High Vacuum Pressure

Scanning electron microscopes (SEM), which image sample surfaces by scanning with an electron beam, are widely used for steric observations of resting samples in basic and applied biology. Various conventional methods exist for SEM sample preparation. However, conventional SEM is not a good tool to observe living organisms because of the associated exposure to high vacuum pressure and electron beam radiation. Here we attempted SEM observations of live ticks. During 1.5×10−3 Pa vacuum pressure and electron beam irradiation with accelerated voltages (2–5 kV), many ticks remained alive and moved their legs. After 30-min observation, we removed the ticks from the SEM stage; they could walk actively under atmospheric pressure. When we tested 20 ticks (8 female adults and 12 nymphs), they survived for two days after SEM observation. These results indicate the resistance of ticks against SEM observation. Our second survival test showed that the electron beam, not vacuum conditions, results in tick death. Moreover, we describe the reaction of their legs to electron beam exposure. These findings open the new possibility of SEM observation of living organisms and showed the resistance of living ticks to vacuum condition in SEM. These data also indicate, for the first time, the usefulness of tick as a model system for biology under extreme condition