Search results for "VARIATION"
showing 10 items of 2124 documents
FLUMO: FLexible Underwater MOdem
2019
The last years have seen a growing interest in underwater acoustic communications because of its applications in marine research, oceanography, marine commercial operations, the offshore oil industry and defense. High-speed communication in the underwater acoustic channel has been challenging because of limited bandwidth, extended multipath, refractive properties of the medium, severe fading, rapid time variation and large Doppler shifts. In this paper, we show an implementation of a flexible Software-Defined Acoustic (SDA) underwater modem, where modulation parameters are completely tunable to optimize performance. In particular, we develop the system architecture following two key ideas. …
Tras la pista del VIH: los estudios evolutivos y la comprensión del sida.
2013
El VIH o virus de la inmunodeficiencia humana tiene un gran impacto sanitario, social y económico; las terapias actuales permiten controlar la infección pero no se ha encontrado tratamiento curativo ni vacuna efectiva. Para conseguir estos objetivos, debe tenerse en cuenta la gran variabilidad genética y rápida evolución del VIH, asociadas, por ejemplo, a la aparición de variantes de resistencia a fármacos o de cambios antigénicos.
From Caristi’s Theorem to Ekeland’s Variational Principle in ${0}_{\sigma }$ -Complete Metric-Like Spaces
2014
We discuss the extension of some fundamental results in nonlinear analysis to the setting of ${0}_{\sigma }$ -complete metric-like spaces. Then, we show that these extensions can be obtained via the corresponding results in standard metric spaces.
Interindividual variability of food memory performance
2008
International audience; To investigate consumer's memory performance for a regularly product, 95 usual consumers of a precise soft-drink were invited to took part in a memory task, during which they were offered a series of samples, consisting in some samples identical to their favourite drink (target samples), and some samples slightly varying in sweetness, sourness of flavour intensity (distractor samples). (...)
Molecular phylogeny and ultrastructure of the lichen microalga Asterochloris mediterranea sp. nov. from Mediterranean and Canary Islands ecosystems
2015
The microalgae of the genus Asterochloris are the preferential phycobionts in Cladonia, Lepraria and Stereocaulon lichens. Recent studies have highlighted the hidden diversity of the genus, even though phycobionts hosting Cladonia spp. in Mediterranean and Canarian ecosystems have been poorly explored. Phylogenetic analyses were made by concatenation of the sequences obtained with a plastid -LSU rDNA- and two nuclear -ITS rDNA and actin- molecular markers of the phycobionts living in several populations of Cladonia convoluta-C. foliacea complex, C. rangiformis and C. cervicornis species widely distributed in these areas in a great variety of substrata and habitats. A new strongly supported …
Vapour partition of aroma compounds in strawberry flavoured custard cream and effect of fat content
2008
International audience; Gas–matrix partition coefficients (k) of volatile compounds of a strawberry flavour added to a complex model system (custard dessert, COST action 921 recipe) were determined. The influence of fat content on the volatility of the strawberry aroma compounds was investigated using full fat milk- (FFM) and skimmed milk- (SM) custards. For the purpose of this study, the phase ratio variation (PRV) method was used because of its easy application for a mixture of volatiles without requiring any calibration. From the 15 aroma compounds present in the flavouring mixture, seven were volatile enough to be detected and concentrated enough to allow the calculation of k values. Ga…
The effects of image compression on quantitative measurements of digital panoramic radiographs
2012
WOS: 000314401800026
On the discreet spectrum of fractional quantum hydrogen atom in two dimensions
2019
We consider a fractional generalization of two-dimensional (2D) quantum-mechanical Kepler problem corresponding to 2D hydrogen atom. Our main finding is that the solution for discreet spectrum exists only for $\mu>1$ (more specifically $1 < \mu \leq 2$, where $\mu=2$ corresponds to "ordinary" 2D hydrogenic problem), where $\mu$ is the L\'evy index. We show also that in fractional 2D hydrogen atom, the orbital momentum degeneracy is lifted so that its energy starts to depend not only on principal quantum number $n$ but also on orbital $m$. To solve the spectral problem, we pass to the momentum representation, where we apply the variational method. This permits to obtain approximate analytica…
Temporal genetic structure in a poecilogonous polychaete: the interplay of developmental mode and environmental stochasticity
2014
Background: Temporal variation in the genetic structure of populations can be caused by multiple factors, including natural selection, stochastic environmental variation, migration, or genetic drift. In benthic marine species, the developmental mode of larvae may indicate a possibility for temporal genetic variation: species with dispersive planktonic larvae are expected to be more likely to show temporal genetic variation than species with benthic or brooded non-dispersive larvae, due to differences in larval mortality and dispersal ability. We examined temporal genetic structure in populations of Pygospio elegans, a poecilogonous polychaete with within-species variation in developmental m…
Modified total variation regularization using fuzzy complement for image denoising
2015
In this paper, we propose a denoising algorithm based on the Total Variation (TV) model. Specifically, we associate to the regularization term of the Rodin-Osher-Fatimi (ROF) functional a small weight whenever denoising is performed in edge and texture regions, which means less regularization and more details preservation. On the other hand, a large weight is associated if the region being filtered is smooth which means noise will be well suppressed. The weight computation is inspired from the fuzzy edge complement. Experiments on well-known images and comparison with state of the art denoising algorithms demonstrate that the proposed method not only presents good denoising performance but …