Search results for "GRI"
showing 10 items of 10209 documents
Size patterns through time: the case of the Early Jurassic ammonite radiation
2002
The shell size of 1236 ammonite species representing all known Early Jurassic faunas is analyzed. Size patterns are studied for the entire period and then at the biozone scale for the first four stages of the Jurassic (28 Myr), during which ammonites recovered from the crisis at the Triassic/Jurassic (T/J) boundary. Our analysis reveals that (1) a size continuum (normal distribution from “dwarfs” to “giants”) exists for all Early Jurassic ammonites; (2) although there are no sustained trends (e.g., no Cope's rule), the succession is not monotonous and patterns may differ conspicuously from one biozone to the next; and (3) increases and decreases in size range are the most frequent evolution…
Comparison of the functional responses of invasive and native amphipods
2008
While we can usually understand the impacts of invasive species on recipient communities, invasion biology lacks methodologies that are potentially more predictive. Such tools should ideally be straightforward and widely applicable. Here, we explore an approach that compares the functional responses (FRs) of invader and native amphipod crustaceans. Dikerogammarus villosus is a Ponto-Caspian amphipod currently invading Europe and poised to invade North America. Compared with other amphipods that it actively replaces in freshwaters, D. villosus exhibited significantly greater predation, consuming significantly more prey with a higher type II FR. This corroborates the known dramatic field imp…
Zu den Ursachen der unterschiedlichen pH-Empfindlichkeit vonGammarus pulex L., G.fossarum KOCH (Amphipoda) undAselus aquaticus L. (Isopoda)
1992
By means of ion chromatography the extensive and significantly higher loss of ions of G. pulex and G. fossarum in acid water (pH 3.0) as compared to neutral water is proved. While cations are being accumulated in the water, some ions (Na+, Cl−) leave the hemolymph in important percentage, others increase highly after being set free from the cells (K+ and Ca2+). The loss of cations with Asellus aquaticus in acid water (pH 3) is clearly lower than with Gammarus, and it is not significantly higher than when the animals are put into neutral water.
Risque phytosanitaire (ARP) portant sur Fusarium oxysporum f. sp. cubense (agent pathogène responsable de la maladie de Panama) pour les départements…
2018
Risque phytosanitaire (ARP) portant sur [i]Fusarium oxysporum[/i] f. sp.[u] cubense[/u] (agent pathogène responsable de la maladie de Panama) pour les départements d'Outre-mer
RESISTANCE AND TOLERANCE IN A HOST PLANT–HOLOPARASITIC PLANT INTERACTION: GENETIC VARIATION AND COSTS
2002
Host organisms are believed to evolve defense mechanisms (i.e., resistance and/or tolerance) under selective pressures exerted by natural enemies. A prerequisite for the evolution of resistance and tolerance is the existence of genetic variation in these traits for natural selection to act. However, selection for resistance and/or tolerance may be constrained by negative genetic correlations with other traits that affect host fitness. We studied genetic variation in resistance and tolerance against parasitic infection and the potential fitness costs associated with these traits using a novel study system, namely the interaction between a flowering plant and a parasitic plant. In this system…
One-Pot Analysis: a New Integrated Methodology for Determination of TAG and FA Determination through LC/MS and in-silico Saponification
2017
Vegetable oils differ significantly for their lipid profile and are mainly constituted by triacylglycerols (TAGs). These are esters formed bonding glycerol to three fatty acids (FAs). To the best of our knowledge, FA and TAG profiles in oils and fats are obtained using at least two different experimental techniques. In particular, FA determination requires elaborated procedures for sample preparation and analyte derivatization. In this work, we propose a one-pot analysis able to determine both TAG and FA contents of edible oils, using experimental data obtained from a simple liquid chromatography/mass spectrometry determination of TAGs. This experimental procedure is followed by an in silic…
Target analysis and retrospective screening of mycotoxins and pharmacologically active substances in milk using an ultra-high-performance liquid chro…
2020
Milk is a nutritious food suitable for infants and adults, and it plays an important role in the human diet. However, it may also be a vehicle for food contaminants. In this report, we developed a method using ultra-high-performance liquid chromatography coupled with high-resolution mass spectrometry (UHPLC-Q-Exactive Orbitrap HRMS; Thermo Fisher Scientific, Waltham, MA) for simultaneous identification of target pharmacologically active substances and mycotoxins in milk. We also used the Q-Orbitrap operating in full scan mode to identify other possible drugs and microbial metabolites that occurred in samples. Fifty-six commercially available milk samples from the Italian market were analyze…
Surface Pretreatment Boosts the Performance of Supramolecular Affinity Materials on Quartz Crystal Microbalances for Sensor Applications
2013
A Teflon-like coating is the key for the boost in sensitivity of quartz microbalances for the tracing of airborne analytes. Since the undesired signals for the interfering compounds are suppressed and the ones for the targeted compounds (e.g., peroxide explosives) are enhanced, the PCA output is improved.
Study of surface layers and ejected powder formed by oxidation of titanium substrates with a pulsed Nd:YAG laser beam.
2009
Laser treatment of a titanium surface at certain conditions initiates the formation of titanium oxide layers as well as micro (nano) scale powder ejected from the surface of the substrate. The resultant morphology of the surface as well as the size and the structure of the particles are all strongly dependent on the treatment parameters (laser fluence, pulse frequency, overlap parameter, etc.). In this study, titanium substrates were treated with an industrial pulsed Nd:YAG laser in air, with varying parameters. Surface layers and ejected materials were compared using scanning and transmission electron microscopy, X-ray diffraction and Raman spectroscopy. The rutile phase of TiO(2) dominate…
Removal of Surface Oxygen Vacancies Increases Conductance Through TiO(2) Thin Films for Perovskite Solar Cells
2019
[Image: see text] We report that UV–ozone treatment of TiO(2) anatase thin films is an efficient method to increase the conductance through the film by more than 2 orders of magnitude. The increase in conductance is quantified via conductive scanning force microscopy on freshly annealed and UV–ozone-treated TiO(2) anatase thin films on fluorine-doped tin oxide substrates. The increased conductance of TiO(2) anatase thin films results in a 2% increase of the average power conversion efficiency (PCE) of methylammonium lead iodide-based perovskite solar cells. PCE values up to 19.5% for mesoporous solar cells are realized. The additional UV–ozone treatment results in a reduced number of oxygen…