55 research outputs found

    Invasive Plants and Enemy Release: Evolution of Trait Means and Trait Correlations in Ulex europaeus

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    Several hypotheses that attempt to explain invasive processes are based on the fact that plants have been introduced without their natural enemies. Among them, the EICA (Evolution of Increased Competitive Ability) hypothesis is the most influential. It states that, due to enemy release, exotic plants evolve a shift in resource allocation from defence to reproduction or growth. In the native range of the invasive species Ulex europaeus, traits involved in reproduction and growth have been shown to be highly variable and genetically correlated. Thus, in order to explore the joint evolution of life history traits and susceptibility to seed predation in this species, we investigated changes in both trait means and trait correlations. To do so, we compared plants from native and invaded regions grown in a common garden. According to the expectations of the EICA hypothesis, we observed an increase in seedling height. However, there was little change in other trait means. By contrast, correlations exhibited a clear pattern: the correlations between life history traits and infestation rate by seed predators were always weaker in the invaded range than in the native range. In U. europaeus, the role of enemy release in shaping life history traits thus appeared to imply trait correlations rather than trait means. In the invaded regions studied, the correlations involving infestation rates and key life history traits such as flowering phenology, growth and pod density were reduced, enabling more independent evolution of these key traits and potentially facilitating local adaptation to a wide range of environments. These results led us to hypothesise that a relaxation of genetic correlations may be implied in the expansion of invasive species

    Measurement of nuclear modification factors of ϒ(1S), ϒ(2S), and ϒ(3S) mesons in PbPb collisions at √sNN = 5.02 TeV

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    The cross sections for ϒ(1S), ϒ(2S), and ϒ(3S) production in lead–lead (PbPb) and proton–proton (pp) collisions at √sNN = 5.02 TeV have been measured using the CMS detector at the LHC. The nuclear modification factors, RAA, derived from the PbPb-to-pp ratio of yields for each state, are studied as functions of meson rapidity and transverse momentum, as well as PbPb collision centrality. The yields of all three states are found to be significantly suppressed, and compatible with a sequential ordering of the suppression, RAA(ϒ(1S)) > RAA(ϒ(2S)) > RAA(ϒ(3S)). The suppression of ϒ(1S) is larger than that seen at √sNN = 2.76 TeV, although the two are compatible within uncertainties. The upper limit on the RAA of ϒ(3S) integrated over pT, rapidity and centrality is 0.096 at 95% confidence level, which is the strongest suppression observed for a quarkonium state in heavy ion collisions to date

    Detection of ultra-low concentrations of bromodihydrochlorophenylbenzodiazepine (phenazepam) and its metabolites in biological objects

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    In extreme situations, reliable detection of the minimum therapeutic concentrations of psychotropic substances is important, since this allows one to provide adequate resuscitation. The group of benzodiazepine derivatives, which includes bromodihydrochlorophenylbenzodiazepine (phenazepam), is widely used in clinical practice. Along with the positive clinical effect, phenazepam has numerous side effects, capable of causing poisoning, even death. The study was aimed to develop the method for detection of the phenazepam metabolites by high-resolution HPLC–TMS suitable for achieving the aims and objectives of forensic medical expertise in case of the ultra-low urine substance concentrations. Urine of six patients (males and females aged 28–40), who were prescribed phenazepam and took the drug at minimum therapeutic concentrations on an ad hoc basis, was used during the study. Optimum conditions for the analyte chromatography after the urine sample preparation were defined with the phenazepam retention time of 7.05 ± 0.06 min; specific ions (m/z) 179, 183, 206, 242, 271, 285, 320, 348 (main) were defined for identification of phenazepam.</jats:p

    Existence and uniqueness of best proximity point for contractions of Geraghty type

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    The purpose of this paper is provide sufficient conditions for the existence of a unique best proximity point for contractions of Geraghty type. Our paper improves a recent result due to Caballero et al. (Fixed Point Theory and Applications. doi: 10.1186/1687-1812-2012-231, 2012).9719570,4020,776Q2Q2Sello FECYTSCI
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