Search results for "COLOR"
showing 10 items of 2721 documents
On Packing Colorings of Distance Graphs
2014
International audience; The {\em packing chromatic number} $\chi_{\rho}(G)$ of a graph $G$ is the least integer $k$ for which there exists a mapping $f$ from $V(G)$ to $\{1,2,\ldots ,k\}$ such that any two vertices of color $i$ are at distance at least $i+1$. This paper studies the packing chromatic number of infinite distance graphs $G(\mathbb{Z},D)$, i.e. graphs with the set $\mathbb{Z}$ of integers as vertex set, with two distinct vertices $i,j\in \mathbb{Z}$ being adjacent if and only if $|i-j|\in D$. We present lower and upper bounds for $\chi_{\rho}(G(\mathbb{Z},D))$, showing that for finite $D$, the packing chromatic number is finite. Our main result concerns distance graphs with $D=…
On Coloring Unit Disk Graphs
1998
In this paper the coloring problem for unit disk (UD) graphs is considered. UD graphs are the intersection graphs of equal-sized disks in the plane. Colorings of UD graphs arise in the study of channel assignment problems in broadcast networks. Improving on a result of Clark et al. [2] it is shown that the coloring problem for UD graphs remains NP-complete for any fixed number of colors k≥ 3 . Furthermore, a new 3-approximation algorithm for the problem is presented which is based on network flow and matching techniques.
Discrete wavelet transform based multispectral filter array demosaicking
2013
International audience; The idea of colour filter array may be adapted to multi-spectral image acquisition by integrating more filter types into the array, and developing associated demosaicking algorithms. Several methods employing discrete wavelet transform (DWT) have been proposed for CFA demosaicking. In this work, we put forward an extended use of DWT for mul-tispectral filter array demosaicking. The extension seemed straightforward, however we observed striking results. This work contributes to better understanding of the issue by demonstrating that spectral correlation and spatial resolution of the images exerts a crucial influence on the performance of DWT based demosaicking.
Synthesis and Spectroscopic Properties of Silica−Dye−Semiconductor Nanocrystal Hybrid Particles
2010
We prepared silica-dye-nanocrystal hybrid particles and studied the energy transfer from semiconductor nanocrystals (= donor) to organic dye molecules (= acceptor). Multishell CdSe/CdS/ZnS semiconductor nanocrystals were adsorbed onto monodisperse Stöber silica particles with an outer silica shell of thickness 2-23 nm containing organic dye molecules (Texas Red). The thickness of this dye layer has a strong effect on the energy transfer efficiency, which is explained by the increase in the number of dye molecules homogeneously distributed within the silica shell, in combination with an enhanced surface adsorption of nanocrystals with increasing dye amount. Our conclusions were underlined by…
Reduction of red-green discrimination by dopamine D1 receptor antagonists and retinal dopamine depletion
1996
AbstractReduction of wavelength discrimination ability in the 560–640 nm range, but not in the 404–540 nm range, has been demonstrated in goldfish after intravitreal injection of D1-dopamine receptor antagonists. Intravitreal injection of the dopaminergic neurotoxin 6-OH-dopamine severely reduced wavelength discrimination ability in the 540–661 nm range within 3 days. Discrimination ability could be reconstituted by the Dl-agonist SKF 38393. Animals recovered from injection of 6-OH-dopamine within 14–16 days. No change of wavelength discrimination was induced by 6-OH-dopamine in the 461–540 nm range. We conclude that under photopic conditions dopamine modulates retinal mechanisms involved i…
Forward rapidity isolated photon production in proton-nucleus collisions
2018
We calculate isolated photon production at forward rapidities in proton-nucleus collisions in the Color Glass Condensate framework. Our calculation uses dipole cross sections solved from the running coupling Balitsky-Kovchegov equation with an initial condition fit to deep inelastic scattering data and extended to nuclei with an optical Glauber procedure that introduces no additional parameters beyond the basic nuclear geometry. We present predictions for future forward RHIC and LHC measurements. The predictions are also compared to updated results for the nuclear modification factors for pion production, Drell-Yan dileptons and $J/\psi$ mesons in the same forward kinematics, consistently c…
Sequencing, De Novo Assembly and Annotation of the Colorado Potato Beetle, Leptinotarsa decemlineata, Transcriptome
2012
Background. The Colorado potato beetle (Leptinotarsa decemlineata) is a major pest and a serious threat to potato cultivation throughout the northern hemisphere. Despite its high importance for invasion biology, phenology and pest management, little is known about L. decemlineata from a genomic perspective. We subjected European L. decemlineata adult and larval transcriptome samples to 454-FLX massively-parallel DNA sequencing to characterize a basal set of genes from this species. We created a combined assembly of the adult and larval datasets including the publicly available midgut larval Roche 454 reads and provided basic annotation. We were particularly interested in diapause-specific g…
A Colorimetric Membrane-Based Sensor with Improved Selectivity towards Amphetamine
2021
Due to their simplicity, speed and low cost, chemical spot tests are increasingly demanded for the presumptive identification of illicit drugs in a variety of contexts such as point-of-care assistance or prosecution of drug trafficking. However, most of the colorimetric reactions used in these tests are, at best, drug class selective. Therefore, the development of tests based on chemical reactions with improved discrimination power is of great interest. In this work, we propose a new colorimetric assay for amphetamine (AMP) based on its reaction with solutions of alkaline gold bromide to form an insoluble yellow–orange derivative. The resulting suspensions are then filtered onto nylon membr…
Natural polyphenols in cancer therapy.
2011
Natural polyphenols are secondary metabolites of plants involved in defense against different types of stress. Extracts containing these compounds have been used for thousands of years in traditional eastern medicine. Polyphenols act on multiple targets in pathways and mechanisms related to carcinogenesis, tumor cell proliferation and death, inflammation, metastatic spread, angiogenesis, or drug and radiation resistance. Nevertheless, reported effects claimed for polyphenols are controversial, since correlations between in vitro effects and in vivo evidence are poorly established. The main discrepancy between health claims versus clinical observations is the frequent use of nonphysiological…
Development of an ion-pair to improve the colon permeability of a low permeability drug: Atenolol.
2016
Abstract To ensure the optimal performance of oral controlled release formulations, drug colon permeability is one of the critical parameters. Consequently developing this kind of formulations for low permeability molecules requires strategies to increase their ability to cross the colonic membrane. The objective of this work is to show if an ion-pair formation can improve the colon permeability of atenolol as a low permeability drug model. Two counter ions have been tested: brilliant blue and bromophenol blue. The Distribution coefficients at pH 7.00 (DpH7) of atenolol, atenolol + brilliant blue and atenolol + bromophenol blue were experimentally determined in n-octanol. Moreover, the colo…