Search results for "VARIABILITY"
showing 10 items of 904 documents
Optimal Source Selection for Image Photoplethysmography
2016
International audience; This paper presents an optimal selection on the region of interest (ROI) and color spaces to extract photoplethysmography signals from facial videos. The study is carried out under two sections; ROI selection and color space selection. We compared five different ROI selection for different regions of the face. We also investigated three color spectrums namely additive, perceptual and orthogonal color spaces. The study experimented on the publicly available human-computer interaction (HCI) database. When evaluated on 30 subjects, the results showed that the ROI selection on the forehead and the green spectrum of the additive color space to provides higher accuracy for…
Geostatistical computing of acoustic maps in the presence of barriers
2009
Acoustic maps are the main diagnostic tools used by authorities for addressing the growing problem of urban acoustic contamination. Geostatistics models phenomena with spatial variation, but restricted to homogeneous prediction regions. The presence of barriers such as buildings introduces discontinuities in prediction areas. In this paper we investigate how to incorporate information of a geographical nature into the process of geostatistical prediction. In addition, we study the use of a Cost-Based distance to quantify the correlation between locations.
Takrolimus w długoterminowym leczeniu immunosupresyjnym biorców przeszczepu nerki — praktyczne wskazówki
2020
Tacrolimus got the position crucial immunosuppressive drug in a solid organ transplantation. For obtaining the best long-term results it is essential an avoidance of excessive dose lowering and maintenance stable drug concentration. The intrapatient tacrolimus concentration variability, which exerts negative impact on the graft survival, should be differentiated from fluctuation, describing distinct pharmacokinetic event, without proven clinical significance. Furthermore, real tacrolimus concentration variability should be separated from variability caused by recipient instability. Among causes of tacrolimus intrapatient variability on the first places are: insufficient adherence to treatme…
L'Oscillation de Madden-Julian et la variabilité pluviométrique régionale en Afrique Subsaharienne
2007
The role of the Madden-Julian Oscillation ("MJO") on rainfall variability in Sub-Saharan Africa is examined, based on daily rain-gauge records and the NCEP-DOE AMIP-II reanalyses. The convective and dynamical signal associated with the MJO is extracted using two differing methodologies, the BMRC daily indices (Wheeler & Hendon 2004) on the one hand, and a Local Mode Analysis ("LMA", Goulet & Duvel 2000) on the other hand. The temporal variability of the MJO (in terms of period, amplitude, seasonality and location of the convective anomalies) is first analysed. Though the overall amplitude of the signal is not related to El Niño, the oscillations occurring under El Niño (La Niña) conditions …
Pluviométrie et circulation atmosphérique simulées par le modèle régional WRF en Afrique australe : sensibilité à la physique et variabilité interne
2011
This study evaluates the capability of the regional climate model WRF to simulate Southern African rainfall and associated atmospheric circulation, particularly over South Africa, a country covered by a dense network of in situ observations. Three sets of simulations are performed at a 35km horizontal resolution during the core of the austral rainy season (December to February: DJF) with 6-hourly forcings provided by ERA40 reanalysis. The first set quantifies sensitivity of the simulated climate to the parameterizations of atmospheric convection, planetary boundary layer and microphysics. The retained case study (DJF 1993-1994: DJF94) is representative of the South African rainfall climatol…
Shaping the antipredator strategy: flexibility, consistency, and behavioral correlations under varying predation threat
2014
9 pages; International audience; Recent ecological and evolutionary research emphasizes the importance of adaptive trait integration. For instance, antipredator defenses are built up of several morphological and behavioral components in many species, yet their functional relationships are still poorly documented. Using field-collected freshwater crustaceans Gammarus fossarum in a within-subject design, we investigated the flexibility and consistency of refuge use, photophobia, and exploration behavior as well as their associations, quantified both when predation risk was absent or artificially simulated. In agreement with the "threat-sensitivity" hypothesis, both refuge use and photophobia …
Differences in allozyme patterns between Diaphanosoma brachyurum and Diaphanosoma mongolianum, as revealed in Central European populations
1995
Recent taxonomic revisions in the genus Diaphanosoma have made the uncertainty in species discrimination with morphological characters obvious. Therefore species characterization on a genetic basis seems to be required. Here we examined the genetic structure of two Diaphanosoma mongolianum populations and three Diaphanosoma brachyurum populations in Central Europe by allozyme electrophoresis. A genetic differentiation between both species was evident. 5 out of 9 tested loci carried diagnostic alleles. Both species differed in their habitat choice: D. mongolianum was adapted to higher trophic levels than D. brachyurum. Co-occurrence was observed in a eutrophic lake. Populations sampled from …
Survey of Citrus tristeza virus in Southern Italy
2010
After a recent detection of Citrus tristeza virus (CTV) in Calabria (Southern Italy), an investigation was initiated in the spring 2006 to survey for the virus in this Region. The survey showed that CTV was not present in the nurseries which indicated that citrus mother plants and citrus plantlets ready for marketing have fulfilled completely the phytosanitary requirements. CTV was not detected in citrus-growing areas of Catanzaro, Cosenza and Crotone Provinces, but was found, at different levels in infected plants, in some orchards located in the Reggio Calabria and Vibo Valentia Provinces. Since the virus was detected not only in material illegally imported from abroad but also in local v…
Selection and long-term cultures of high-yielding Digitalis obscura plants: RAPD markers for analysis of genetic stability
1996
Fifteen wild-growing plants of Digitalis obscura collected in three differents regions were characterized according to their capacities to biosynthesize cardenolides and to proliferate in vitro. Great genotype-dependent variabilities were found in both parameters. Selected genotypes were differentiated using randomly amplified polymorphic DNA (RAPD) markers. Once an elite genotype with high-yielding properties was isolated and micropropagated during 2 years, identity of the donor plant and the regenerants was confirmed by RAPD analysis.
The effect of periodic bottlenecks on the competitive ability of Drosophila pseudoobscura lines.
1993
Competition experiments between several Drosophila pseudoobscura strains that were previously subjected to periodic bottlenecks of different sizes and D. willistoni have been carried out. Contrary to previous results with these two species, where stable coexistence was detected, populations of D. pseudoobscura displaced D. willistoni in a few generations. By using a relative fitness measure, the control lines (that had not gone through bottlenecks) outcompeted D. willistoni faster than bottlenecked lines. One of these, corresponding to the minimum possible bottleneck size of one pair, also shows significantly lower relative fitness than the other strains. These results are discussed in rela…