Search results for "GREG"
showing 10 items of 1242 documents
The increasing temperature as driving force for spatial distribution patterns of Parapenaeus longirostris (Lucas 1846) in the Strait of Sicily (Centr…
2020
Abstract The deep-water rose shrimp Parapenaeus longirostris (DPS), a demersal decapod representing the most important component of crustacean landings in the Mediterranean Sea, has been suggested as a species that may exhibit temperature-driven changes in the spatio-temporal dynamics. Considering that Mediterranean waters are warming up faster than oceans, understanding the relationships of DPS populations with temperature variations and the related changes in spatial patterns is absolutely key for its management. Using a long-term dataset covering 13-years from scientific surveys (International Bottom Trawl-Surveys in the Mediterranean, MEDITS; Italian national trawl surveys, GRUND) in th…
Zeolite-silver-zinc nanoparticles : biocompatibility and their effect on the compressive strength of mineral trioxide aggregate
2016
Background This study was carried out to evaluate the biocompatibility of zeolite-silver-zinc (Ze-Ag-Zn) nanoparticles and their effect on the compressive strength of Mineral Trioxide Aggregate (MTA). Material and Methods Biocompatibility was evaluated by an MTT assay on the pulmonary adenocarcinoma cells with 0.05, 0.1, 0.25, 0.5, 1 and 5 mg/mL concentrations of Ze-Ag-Zn. For compressive strength test, four groups containing 15 stainless-steel cylinders with an internal diameter of 4 and a height of 6 mm were prepared and MTA (groups 1 and 2) or MTA + 2% Ze-Ag-Zn (groups 3 and 4) were placed in the cylinders. The compressive strength was evaluated using a universal testing machine 4 days a…
Spatial segregation and realized niche shift during the parallel invasion of two olive subspecies in south-eastern Australia.
2015
12 pages; International audience; AimGreater understanding of the processes underlying biological invasions is required to determine and predict invasion risk. Two subspecies of olive (Olea europaea subsp. europaea and Olea europaea subsp. cuspidata) have been introduced into Australia from the Mediterranean Basin and southern Africa during the 19th century. Our aim was to determine to what extent the native environmental niches of these two olive subspecies explain the current spatial segregation of the subspecies in their non-native range. We also assessed whether niche shifts had occurred in the non-native range, and examined whether invasion was associated with increased or decreased oc…
Glomales species associated with surface and deep rhizosphere of Faidherbia albida in Senegal
2000
Five arbuscular mycorrhizal (AM) fungal species were isolated and propagated from surface and deep rhizospheres of Faidherbia albida trees growing in two ecoclimatic zones of West Africa: the semi-arid Sahelian and the more humid Sudano-Guinean areas. Of these species, Glomus aggregatum, Glomus caledonium, and Glomus mosseae were trapped by F. albida roots when cultivated with either surface or deep soils. Glomus fasciculatum was found exclusively at the semi-arid Sahelian sites of Louga and Diokoul and Gigaspora margarita was isolated only from 16.5-m and 34-m-deep samples. Comparable glomalean fungal species richness was identified in deep (1.5–34 m) and surface (0.15 m) samples. The isol…
Artificial Oral Processing of Extruded Pea Flour Snacks
2021
International audience; The structure of extruded pea flour can affect chewing performances. Our objective was to relate the bolus properties (fragmentation, moisture content and viscosity) of chewed extruded pea snacks to their structure. In order to have control over oral physiological parameters, we opted for an in vitro approach using a chewing simulator, the variables of which were the flow rate of artificial salivary fluid and chewing time. The structure of the extruded pea snacks was characterized by its density and protein solubility in dithioerythritol (DTE), which reflected the amount of protein aggregates cross-linked by disulphide bonds. The particle size distribution and median…
Preferential assimilation of seagrass detritus by two coexisting Mediterranean sea cucumbers: Holothuria polii and Holothuria tubulosa
2019
Abstract Holothuria polii and Holothuria tubulosa are two of the most commercially exploited sea cucumbers of the Mediterranean Sea. As deposit-feeders, they represent an important component of the benthic community. Hence, knowledge of their feeding behaviour is crucial for understanding their function in terms of benthic ecology and sediment dynamics. Using information obtained from stable isotope analysis, the food selectivity/assimilation, temporal variations in diet and trophic niche of H. polii and H. tubulosa were investigated. Analysis of carbon and nitrogen isotopic ratios in body wall tissue showed a preferential assimilation of seagrass detritus among multiple food sources, with …
Disjunct populations of European vascular plant species keep the same climatic niches
2015
Aim Previous research on how climatic niches vary across species ranges has focused on a limited number of species, mostly invasive, and has not, to date, been very conclusive. Here we assess the d ...
Growth stimulation of seventeen fallow leguminous plants inoculated with Glomus aggregatum in Senegal
2001
Abstract Tropical legumes from fallowed areas in Senegal were inoculated with a tropical strain of Glomus aggregatum to test their relative mycorrhizal dependency in a greenhouse experiment. Twelve species among the seventeen tested showed a significant growth increase when mycorrhizal. Their mycorrhizal dependency varied from 92.7% for Indigofera stenophylla to 26.2% for Prosopis julifora . A significant positive correlation was found between mycorrhizal dependency and root hair length. The results confirm the high mycorrhizal dependency of legumes which are economically very important in the restoration of soil fertility of fallowed areas in the Sahelian and Soudano-Sahelian zones.
Habitat assessment by parasitoids: consequences for population distribution
2006
International audience; The ideal free distribution (IFD) is a stable distribution of competitors among resource patches. For equally efficient competitors, equilibrium is reached when the per capita rate of intake equalizes across patches. The seminal version of the IFD assumes omniscience, but populations may still converge toward the equilibrium provided that competitors 1) accurately assess their environment by learning and 2) remain for an optimal (rate-maximizing) time on each encountered patch. In the companion article (Tentelier C, Desouhant E, Fauvergue X. 2006. Habitat assessment by parasitoids: mechanisms for patch time allocation. Behav Ecol. Forthcoming), it is shown that the p…
Food-web structure and mercury dynamics in a large subarctic lake following multiple species introductions
2016
Summary The rate of non-native fish introductions into freshwater ecosystems has more than doubled during the past three decades, posing a serious threat to native biodiversity. Despite potential benefits for fisheries, little is known about how introduced species interact with native communities at the food-web level, or impact energy transfer dynamics and accumulation of contaminants in lake ecosystems. Here, we explored the trophic structure of a large, oligotrophic subarctic lake and assessed the trophic niche use and potential ecosystem-wide consequences of two introduced salmonid species: piscivorous lake trout (Salvelinus namaycush) and zooplanktivorous vendace (Coregonus albula). We…