Search results for "medium"
showing 10 items of 3746 documents
Depositional environments and iron ooid formation in condensed sections (Callovian Oxfordian, South-eastern part of the Paris basin, France)
2005
Carbonate platforms across Western Europe were superseded at the Middle–Upper Jurassic (Callovian–Oxfordian) boundary either by alternating marl–limestone and widespread marl deposits or by condensed sections containing iron ooids. The characteristics of marine condensed sections in the south-eastern part of the Paris Basin (France) and their distribution pattern are examined here, and a model of iron ooid formation is developed. Iron ooids are found from the shoreface to the offshore zone. They are most abundant in the median-to-distal offshore transition zone, where they originally formed. They also occur commonly, albeit often as reworked grains, in the proximal offshore zone, to which t…
Revised phosphate-water fractionation equation reassessing paleotemperatures derived from biogenic apatite.
2010
8 pages; International audience; Oxygen isotopes of biogenic apatite have been widely used to reassess anomalous temperatures inferred from oxygen isotope ratios of ancient biogenic calcite, more prone to diagenetic alteration. However, recent studies have highlighted that oxygen isotope ratios of biogenic apatite differ dependent on used analytical techniques. This questions the applicability of the phosphate–water fractionation equations established over 25 years ago using earlier analytical techniques to more recently acquired data. In this work we present a new phosphate–water oxygen isotope fractionation equation based on oxygen isotopes determined on fish raised in aquariums at contro…
Landscape and wood-fuel in Akrotiri (Thera, Greece) during the Bronze Age
2017
Abstract Wood charcoal macroremains originating from the archaeological site of Akrotiri, Thera (Greece) have been analyzed. The results obtained suggest the existence of thermophilous vegetation on the island from the Early Cycladic period right up to the catastrophic eruption of the volcano in the Late Cycladic I period. The comparative evaluation of the results gained from this study and the previous ones indicates that during the Early Cycladic period an open Pinus type brutia/halepensis (Cyprus/Aleppo pine) forest prevailed on the island, accompanied by maquis vegetation. From the Middle Cycladic period and onwards a shift towards open maquis vegetation is observed. At the same time, s…
Wood as a structural element in the houses of Akrotiri on Thera, Greece. The anthracological evidence
2021
Abstract The highly destructive eruption of the volcano of Santorini during the Late Cycladic I period as a fortunate consequence caused the buildings of the archaeological site of Akrotiri on Thera (Greece) to be remarkably well preserved. The present study deals with wood charcoal macroremains from the construction timbers of two buildings from this site, namely Xeste 3, a semi-public building and the House of the Ladies, a private building. The data suggest the extensive use of Olea europaea for the construction of the wooden floors of the upper storeys, the doors and the infrastructure of the walls. Other taxa systematically used for the beams of the floors of the upper storeys were Pin…
Different parts of the same plants. Charcoals and seeds from Cova de les Cendres (Alicante, Spain)
2018
Abstract The analysis of archaeobotanical macroremains from Cova de les Cendres (Teulada-Moraira, Alicante, Spain) allows a better understanding of the dynamic of the vegetation during the Upper Palaeolithic in the region. The anthracological sequence shows that Pinus type nigra/sylvestris dominates in the area during the Upper Palaeolithic, while more open formations of Juniperus and Fabaceae spread in Upper Solutrean and Early-Middle Magdalenian. The carpological analysis that has been carried out in the Middle Magdalenian level has brought to light different species of Juniperus (J. sabina, J. communis and J. oxycedrus). This information indicates that during the period, Cova de les Cend…
The aminophosphonate glyphosine enhances phycobiliprotein yields from selected cyanobacterial cultures
2017
Among added-value products obtained from cyanobacterial cultures are phycobiliproteins, photosynthetic pigments that have found an increasing number of applications as natural dyes for food, cosmetics, pharmaceuticals, and antioxidants. To obtain sustainable production, we aimed at maximizing phycobilin yield through the increase of either the final biomass or the specific content of these pigments by varying culture parameters, such as chemical composition and pH of the medium or quality and intensity of the light. Here, we report that the addition to the culture medium of millimolar or submillimolar concentrations of the aminophosphonate glyphosine [(N,N-bis(phosphonomethyl)glycine], form…
Adhesion enhancement of cribellate capture threads by epicuticular waxes of the insect prey sheds new light on spider web evolution
2017
To survive, web-building spiders rely on their capture threads to restrain prey. Many species use special adhesives for this task, and again the majority of those species cover their threads with viscoelastic glue droplets. Cribellate spiders, by contrast, use a wool of nanofibres as adhesive. Previous studies hypothesized that prey is restrained by van der Waals' forces and entrapment in the nanofibres. A large discrepancy when comparing the adhesive force on artificial surfaces versus prey implied that the real mechanism was still elusive. We observed that insect prey's epicuticular waxes infiltrate the wool of nanofibres, probably induced by capillary forces. The fibre-reinforced composi…
Sex-specific compensatory growth in the larvae of the greater wax moth Galleria mellonella
2017
Deficiency of food resources in ontogeny is known to prolong an organism's developmental time and affect body size in adulthood. Yet life‐history traits are plastic: an organism can increase its growth rate to compensate for a period of slow growth, a phenomenon known as ‘compensatory growth’. We tested whether larvae of the greater wax moth Galleria mellonella can accelerate their growth after a fast of 12, 24 or 72 h. We found that a subgroup of female larvae showed compensatory growth when starved for 12 h. Food deficiency lasting more than 12 h resulted in longer development and lower mass gain. Strength of encapsulation reactions against a foreign body inserted in haemocoel was the wea…
Cultivar- and Wood Area-Dependent Metabolomic Fingerprints of Grapevine Infected by Botryosphaeria Dieback
2020
International audience; Botryosphaeria dieback is one of the most significant grapevine trunk diseases that affects the sustainability of the vineyards and provokes economic losses. The causal agents, Botryosphaeriaceae species, live in and colonize the wood of the perennial organs causing wood necrosis. Diseased vines show foliar symptoms, chlorosis, or apoplexy, associated to a characteristic brown stripe under the bark. According to the susceptibility of the cultivars, specific proteins such as PR-proteins and other defense-related proteins are accumulated in the brown stripe compared with the healthy woody tissues. In this study, we enhanced the characterization of the brown stripe and …
Flashing light emitting diodes (LEDs) induce proteins, polyunsaturated fatty acids and pigments in three microalgae
2020
As the periodic emission of light pulses by light emitting diodes (LEDs) is known to stimulate growth or induce high value biocompounds in microalgae, this flashing light regime was tested on growth and biochemical composition of the microalgae Nannochloropsis gaditana, Koliella antarctica and Tetraselmis chui. At low flashing light frequencies (e.g., 5 and 50 Hz, Duty cycle = 0.05), a strain-dependent growth inhibition and an accumulation of protein, polyunsaturated fatty acids, chlorophyll or carotenoids (lutein, β-carotene, violaxanthin and neoxanthin) was observed. In addition, a 4-day application of low-frequency flashing light to concentrated cultures increased productivities of eicos…