Search results for " code"
showing 10 items of 636 documents
Combinatorial Gray codes for classes of pattern avoiding permutations
2007
The past decade has seen a flurry of research into pattern avoiding permutations but little of it is concerned with their exhaustive generation. Many applications call for exhaustive generation of permutations subject to various constraints or imposing a particular generating order. In this paper we present generating algorithms and combinatorial Gray codes for several families of pattern avoiding permutations. Among the families under consideration are those counted by Catalan, Schr\"oder, Pell, even index Fibonacci numbers and the central binomial coefficients. Consequently, this provides Gray codes for $\s_n(\tau)$ for all $\tau\in \s_3$ and the obtained Gray codes have distances 4 and 5.
A Watermarking of Medical Image : New Approach Based On "Multi-Layer" Method
2011
In order to contribute to security sharing and transmission of medical images, this paper propose a new approach for Watermarking image based on the techniques of Code Division Multiple Access (CDMA), Discrete Wavelet transform (DWT) and Error Correcting Code (ECC). The motivation of this approach is to improve the quantity of data integration with the conservation of the image visual quality. Therefore, this work permits to the user the capacity to correct the possible alterations if it exists. IRM and Echographic medical image are used to experiment this approach.
The UV Index on the Spanish Mediterranean Coast¶
2005
An analysis is made of measured ultraviolet erythemal solar radiation (UVER) data recorded during the year 2003 by the networks of the Catalan Weather Service and the Environment Department of Valencia (both on the Spanish Mediterranean coast). Results show a latitudinal variation at sea level, of 3-4% per degree and an increase with altitude of 10% per km. Based on these data the UV Index has been evaluated for the measuring stations. The maximum experimental value of the UV Index was around 9 during the summer, although higher values were recorded at two stations, one at the highest elevation and the other at the lowest latitude. The annual accumulated doses of irradiation on a horizontal…
Platyzoan mitochondrial genomes.
2012
Platyzoa is a putative lophotrochozoan (spiralian) subtaxon within the protostome clade of Metazoa, comprising a range of biologically diverse, mostly small worm-shaped animals. The monophyly of Platyzoa, the relationships between the putative subgroups Platyhelminthes, Gastrotricha and Gnathifera (the latter comprising at least Gnathostomulida, "Rotifera" and Acanthocephala) as well as some aspects of the internal phylogenies of these subgroups are highly debated. Here we review how complete mitochondrial (mt) genome data contribute to these debates. We highlight special features of the mt genomes and discuss problems in mtDNA phylogenies of the clade. Mitochondrial genome data seem to be …
Histone deacetylase A key enzyme for the binding of regulatory proteins to chromatin
1993
AbstractCore histones can be modified by reversible, posttranslational acetylation of specific lysine residues within the N-terminal protein domains. The dynamic equilibrium of acetylation is maintained by two enzyme activities, histone acetyltransferase and histone deacetylase. Recent data on histone deacetylases and on anionic motifs in chromatin- or DNA-binding regulatory proteins (e.g. transcription factors, nuclear proto-oncogenes) are summarized and united into a hypothesis which attributes a key function to histone deacetylation for the binding of regulatory proteins to chromatin by a transient, specific local increase of the positive charge in the N-terminal domains of nucleosomal c…
Genomic determinants of protein folding thermodynamics in prokaryotic organisms.
2004
Here we investigate how thermodynamic properties of orthologous proteins are influenced by the genomic environment in which they evolve. We performed a comparative computational study of 21 protein families in 73 prokaryotic species and obtained the following main results. (i) Protein stability with respect to the unfolded state and with respect to misfolding are anticorrelated. There appears to be a trade-off between these two properties, which cannot be optimized simultaneously. (ii) Folding thermodynamic parameters are strongly correlated with two genomic features, genome size and G+C composition. In particular, the normalized energy gap, an indicator of folding efficiency in statistical…
Attendibilità dei modelli per la valutazione dei moduli elastici delle murature suggeriti dalle norme tecniche
2012
In this paper the results of an experimental investigation aimed to the assessment of Young moduli, rigidity moduli and other mechanical properties for different types of masonry are shown. The mechanical characteristics predicted by models proposed by some technical codes were compared against experimental data. This study was motivated by the suggestion of the Masonry Standards Joint Committee's (MSJC) code that, while proposing the use of such models, acknowledges the lack of testing in support of their validation. The experimental investigation has included compressive tests on components (blocks and mortar), diagonal compressive tests and ordinary compressive tests (orthogonally to bed…
Modelling of Orientational Ordering in Lipid Monolayers
1993
Lipid monolayers at high densities are modelled as rigid rods grafted to an interface at the sites of a regular lattice. The transition between the state where the rods are uniformly tilted to a disordered state with no (average) tilt is studied by computer simulation methods. For the one-dimensional model, the molecular dynamics approach is found much less suitable to equilibrate the system rather than Monte Carlo methods. Both in d=2 discretized versions of Monte Carlo codes are much more efficient than continuum Monte Carlo methods, in spite of huge storage requirements. While in d=l the transition occurs at temperature T=0 via the spontaneous creation of solitons, at d=2 a finite temper…
CODING PARTITIONS OF REGULAR SETS
2009
A coding partition of a set of words partitions this set into classes such that whenever a sequence, of minimal length, has two distinct factorizations, the words of these factorizations belong to the same class. The canonical coding partition is the finest coding partition that partitions the set of words in at most one unambiguous class and other classes that localize the ambiguities in the factorizations of finite sequences. We prove that the canonical coding partition of a regular set contains a finite number of regular classes and we give an algorithm for computing this partition. From this we derive a canonical decomposition of a regular monoid into a free product of finitely many re…
Botanical names in Southern Hemisphere Veronica (Plantaginaceae ): sect. Detzneria , sect. Hebe , and sect. Labiatoides
2007
The classification of the Southern Hemisphere Veronica complex is discussed in the light of recent findings that these segregate genera are nested within the hitherto northern Veronica clade. In order to render Veronica monophyletic, we transfer Chionohehe, Derwentia, Detzneria, Hebe, Hebejeebie, Heliohebe, Leonohebe, and Parahebe to Veronica subgen. Pseudoveronica. Correct names are listed for all species in Veronica subgen. Pseudoveronica, according to the International Code of Botanical Nomenclature. Those species previously included in Derwentia together with other Australian species of Veronica are now classified in Veronica sect. Labiatoides, that in Detzneria is now classified in Ver…