Search results for "Environmental conditions"
showing 10 items of 13 documents
Variation in the immune state of Gammarus pulex (Crustacea, Amphipoda) according to temperature: are extreme temperatures a stress?
2017
9 pages; International audience; Temperature is known to impact host-parasite interactions in various ways. Such effects are often regarded as the consequence of the increased metabolism of parasites with increasing temperature. However, the effect of temperature on hosts' immune system could also be a determinant. Here we assessed the influence of temperature on the immunocompetence of the crustacean amphipod Gammarus pulex. Amphipods play a key ecological role in freshwater ecosystems that can be altered by several parasites. We investigated the consequences of three weeks of acclimatization at four temperatures (from 9 °C to 17 °C) on different immunological parameters. Temperature influ…
Testing the potential significance of different scion/rootstock genotype combinations on the ecology of old cultivated olive trees in the southeast M…
2017
Background A previous multi-locus lineage (MLL) analysis of SSR-microsatellite data of old olive trees in the southeast Mediterranean area had shown the predominance of the Souri cultivar (MLL1) among grafted trees. The MLL analysis had also identified an MLL (MLL7) that was more common among rootstocks than other MLLs. We here present a comparison of the MLL combinations MLL1 (scion)/MLL7 (rootstock) and MLL1/MLL1 in order to investigate the possible influence of rootstock on scion phenotype. Results A linear regression analysis demonstrated that the abundance of MLL1/MLL7 trees decreases and of MLL1/MLL1 trees increases along a gradient of increasing aridity. Hypothesizing that grafting o…
Behavioural responses of breeding arctic sandpipers to ground-surface temperature and primary productivity
2021
Most birds incubate their eggs, which requires time and energy at the expense of other activities. Birds generally have two incubation strategies: biparental where both mates cooperate in incubating eggs, and uniparental where a single parent incubates. In harsh and unpredictable environments, incubation is challenging due to high energetic demands and variable resource availability. We studied the relationships between the incubation behaviour of sandpipers (genus Calidris) and two environmental variables: temperature and a proxy of primary productivity (i.e. NDVI). We investigated how these relationships vary between incubation strategies and across species among strategies. We also stud…
Temperature regulating floral bud differentiation in loquat (Eriobotrya japonica Lindl.). Hormonal and genetic aspects
2017
In loquat, apex of a current shoot changes from vegetative to reproductive stage during summer, i.e. under high temperature conditions. Indeed, just before floral bud differentiation, a decline in the growth rate due to high temperature takes place. The aim of this work is to study the role of this 'summer rest period' on the apex transition from vegetative to reproductive stage. For this purpose 1) sprouting of secondary shoots was promoted at different times, removing the main shoot, before, during and after floral bud differentiation occurred and 2) groups of trees were shifted to a greenhouse under average maximum temperature not exceeding 25 ° C during different periods from June to Oc…
Absence of Sex Differential Plasticity to Light Availability during Seed Maturation in Geranium sylvaticum
2015
Sex-differential plasticity (SDP) hypothesis suggests that since hermaphrodites gain fitness through both pollen and seed production they may have evolved a higher degree of plasticity in their reproductive strategy compared to females which achieve fitness only through seed production. SDP may explain the difference in seed production observed between sexes in gynodioecious species in response to resource (nutrients or water) availability. In harsh environments, hermaphrodites decrease seed production whereas females keep it relatively similar regardless of the environmental conditions. Light availability can be also a limiting resource and thus could theoretically affect differently femal…
Suitability of some existing damage indexes for assessing agreements in maintenance and management of museum climatization systems
2020
Heating, Ventilating and Air-Conditioning systems in museums are called to properly control important microclimate parameters, not only for visitors’ wellbeing, but mostly for the preservation of works of art. Accordingly, in case of interruptions to Heating, Ventilating and Air-Conditioning systems, due to maintenance interventions or drawbacks, it is essential to guarantee the acceptable break from service to which possible damages for the works of art are related. In this regard, the aim of this work is to introduce a simple indicator to support curators in regulating the stipulation of contracts with external companies, a more effective management and maintenance of the Heating, V…
Turonian-Maastrichtian biostratigraphy and isotope stratigraphy of the Kopet-Dagh Basin deposits, northeastern Neo-Tethys, Iran
2021
Abstract Planktonic foraminiferal biostratigraphy and isotope stratigraphy analyses of Turonian-Maastrichtian deposits have been carried out in the western part of the Kopet-Dagh Basin. The identification of the planktonic foraminiferal assemblages has led to the recognition of twelve Upper Cretaceous zones (Helvetoglobotruncana helvetica Zone to the Contusotruncana contusa-Abathomphalus mayaroensis zone) from the Tethyan realm. The obtained stable carbon isotope profile correlates with other reference curves, revealing many Late Cretaceous events including the Hitchwood, Navigation, Light Point, East Cliff, White Fall, Late Campanian Event (LCE), Campanian-Maastrichtian Boundary Event (CMB…
Different key roles of mesoscale oceanographic structures and ocean bathymetry in shaping larval fish distribution pattern: A case study in Sicilian …
2016
Fish larvae data collected in year 2009 were used to examine the effects of particular environmental conditions on the structure of larvalassemblages in two oligotrophic Mediterranean areas (the Southern Tyrrhenian Sea and the Strait of Sicily). For this purpose, relationships with environmental variables (temperature, salinity and fluorescence), zooplankton biomass, water circulation and bathymetry are discussed. Hydrodynamic conditions resulted very differently between two study areas. The Southern Tyrrhenian Sea was characterized by moderate shallow circulation compared to the Strait of Sicily. In this framework, distribution pattern of larval density in the Tyrrhenian Sea was mainly dri…
Theoretical study on hydrogen storage capacity of expanded h-BN systems
2017
In this work, the hydrogen storage capacity of the expanded hexagonal Boron Nitride (eh-BN) systems has been presented. We have employed a new equation of state (EOS) for hydrogen gas to figure out the hydrogen density distribution profiles in the eh-BN systems. In this regard, the environmental conditions (i.e., temperature and pressure) are considered in the prediction procedure using DFT single point calculations. The eh-BN systems with different layer spacings are studied by PBE method with consideration of the long range dispersion corrections. On account of the in-plane polar bonds, a series of adsorption positions are considered. Additionally, the adsorption energy and hydrogen densi…
Exploring the conditions of English language education through the experience of Eritrean Sophomore English language learners and teachers
2023
This study addresses the little studied context of English language education in Eritrea. Despite the teaching of English as a subject and the forward-looking mother tongue policy implemented in Eritrean elementary education, Eritrean students struggle to cope with English as the medium of instruction from the start of junior school to the end of tertiary education. This qualitative study analyses sixteen sophomore student interviews and six teacher interviews to critically explore the conditions of English language education in Eritrea. Using an ecological perspective, the findings from this study highlight how the affective, didactic, study and linguistic conditions interrelate with one a…