51 research outputs found
Hyperbolic dimension of Julia sets of meromorphic maps with logarithmic tracts
We prove that for meromorphic maps with logarithmic tracts (e.g. entire or
meromorphic maps with a finite number of poles from class ), the
Julia set contains a compact invariant hyperbolic Cantor set of Hausdorff
dimension greater than 1. Hence, the hyperbolic dimension of the Julia set is
greater than 1.Comment: 7 pages, 1 figur
Genetic differentiation of brackish water populations of cod Gadus morhua in the southern Baltic, inferred from genotyping using SNP-arrays
The Baltic is a semi-enclosed sea characterised by decreasing salinity in the eastern and northern direction with only the deeper parts of the southern Baltic suitable as spawning grounds for marine species like cod. Baltic cod exhibits various adaptations to brackish water conditions, yet the inflow of salty North Sea water near the bottom remains an influence on the spawning success of the Baltic cod. The eastern Baltic population has been very weakly studied in comparison with the western population.
The aim of this study is to demonstrate for the first time genetic differentiation by the use of a large number of SNPs between eastern and western Baltic populations existing in differentiated salinity conditions. Two cod samples were collected from the Bay of Gdańsk, Poland and one from the Kiel Bight, Germany. Samples were genotyped using a cod derived SNP-array (Illumina) with 10 913 SNPs. A selection of diagnostic SNPs was performed. A set of 7944 validated SNPs were analysed to assess the differentiation of three samples of cod. Results indicated a clear distinctness of the Kiel Bight from the populations of the eastern Baltic. FST comparison between both eastern samples was non-significant. Clustering analysis, principal coordinates analysis and assignment test clearly indicated that the eastern samples should be considered as one subpopulation, well differentiated from the western subpopulation. With the SNP approach, no differentiation between groups containing ‘healthy’ and ‘non-healthy’ cod individuals was observed
Entire functions with Julia sets of positive measure
Let f be a transcendental entire function for which the set of critical and
asymptotic values is bounded. The Denjoy-Carleman-Ahlfors theorem implies that
if the set of all z for which |f(z)|>R has N components for some R>0, then the
order of f is at least N/2. More precisely, we have log log M(r,f) > (N/2) log
r - O(1), where M(r,f) denotes the maximum modulus of f. We show that if f does
not grow much faster than this, then the escaping set and the Julia set of f
have positive Lebesgue measure. However, as soon as the order of f exceeds N/2,
this need not be true. The proof requires a sharpened form of an estimate of
Tsuji related to the Denjoy-Carleman-Ahlfors theorem.Comment: 17 page
Radio-Continuum Study of the Nearby Sculptor Group Galaxies. Part 2: NGC 55 at {\lambda}=20, 13, 6 and 3 cm
A series of new radio-continuum ({\lambda}=20, 13, 6 and 3 cm) mosaic images
focused on the NGC55 galactic system were produced using archived observational
data from the Australia Telescope Compact Array. These new images are both very
sensitive (down to rms=33 {\mu}Jy) and feature high angular resolution (down to
<4"). Using these newly created images, 66 previously unidentified discrete
sources are identified. Of these sources, 46 were classified as background
sources, 11 as HII regions and 6 as supernova remnant candidates. This
relatively low number of SNR candidates detected coupled with the low number of
large HII regions is consistent with the estimated low star formation rate of
the galaxy at 0.06 solar masses per year. Our spectral index map shows that the
core of galaxy appears to have a shallow spectral index between {\alpha} = -0.2
and -0.4. This indicates that the core of the galaxy is a region of high
thermal radiation output.Comment: 11 pages, 8 figures. Accepted for publication in Astrophysics and
Space Scienc
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