Search results for "ECU"
showing 10 items of 42395 documents
High-resolution spectroscopy and analysis of the V2 + V3 combination band of SF6 in a supersonic jet expansion
2013
International audience; Sulphur hexafluoride is a very strong greenhouse gas whose concentration is increasing in the atmosphere. It is detected through infrared absorption spectroscopy in the strong ν3 fundamental region. Due to the existence of low-lying vibrational states of this molecule, however, many hot bands arise at room temperature and those are still not known. We present here a contribution to the elucidation of this hot band structure, by analysing the ν2 + ν3 combination band. We use a supersonic jet expansion high-resolution spectrum at a rotational temperature of ca. 25 K that was recorded thanks to the Jet-AILES setup at the Source Optimisée de Lumière d'Energie Intermédiai…
Ancient DNA from European early neolithic farmers reveals their near eastern affinities.
2010
The first farmers from Central Europe reveal a genetic affinity to modern-day populations from the Near East and Anatolia, which suggests a significant demographic input from this area during the early Neolithic.
New data about the landscape of the first occupation of Mallorca: Coval Simó (Escorca, Mallorca)
2020
The Coval Simó shelter provides some of the oldest evidence for settlement on the island of Mallorca and the Balearic archipelago. It also has the peculiarity of being a habitat in a mountain area, so that the human groups that settled there had to adapt their agricultural and farming system to this environment. The plant remains (wood charcoal and seeds) recovered in the occupation levels allow us to address these issues, since they are the result of the different activities developed in this cavity: fuel for domestic activities, food for livestock, etc. The results of this study show that between the III and II millennium cal BC, an agricultural system based on livestock and cereal farmi…
Environmental responses of past and recent agropastoral activities on south Greenlandic ecosystems through molecular biomarkers
2016
Paleoenvironmental studies previously performed on Lake Igaliku revealed two agropastoral phases in south Greenland: the Norse settlement from AD 986 to ca. AD 1450 and the recent installation of sheep farmers, since the 1920s. To improve the knowledge of the timing and magnitude of the Greenlandic agropastoral activities, a lipid inventory was realized and compared with biological and geochemical data. During the 12th century, a major increase in deoxycholic acid (DOC) and coprophilous fungal spores revealed a maximum of herbivores. Synchronously, a minimum of the n-C29/ n-C31 alkane ratio and tree and shrub pollen and a maximum of triterpenyl acetates showed a reduction in the tree and s…
Influence of dissolved organic matter on rare earth elements and yttrium distributions in coastal waters
2010
International audience; Data collected during this study indicate that dissolved Y and REE (rare earth element) behaviour can be monitored through shale-normalised ratios. Relationships occurring between these ratios suggest that leaching from lithogenic materials is the main source of REE in the studied area. This process involves riverine detrital matter in the inner area of the Gulf of Palermo. Features of shale-normalised patterns and the relationship recognised between dissolved Fe and Y/Ho suggest that REE are released from Fe-rich coatings of atmospheric dust. Observed similarities between dissolved Fe and chlorophyll- content suggest that leaching of Fe-rich atmospheric particulates…
Seismites resulting from high-frequency, high-magnitude earthquakes in Latvia caused by Late Glacial glacio-isostatic uplift
2016
Abstract Geologically extremely rapid changes in altitude by glacial rebound of the Earth crust after retreat of the Scandinavian Ice Sheet at the end of the last Weichselian glaciation influenced the palaeogeography of northern Europe. The uplift of the Earth crust apparently was not gradual, but shock-wise, as the uplift was accompanied by frequent, high-magnitude earthquakes. This can be deduced from strongly deformed layers which are interpreted as seismites. Such seismites have been described from several countries around the Baltic Sea, including Sweden, Germany and Poland. Now similarly deformed layers that must also be interpreted as seismites, have been discovered also in Latvia, a…
How ocean acidification can benefit calcifiers.
2017
Reduction in seawater pH due to rising levels of anthropogenic carbon dioxide (CO2) in the world's oceans is a major force set to shape the future of marine ecosystems and the ecological services they provide [1,2]. In particular, ocean acidification is predicted to have a detrimental effect on the physiology of calcifying organisms [3]. Yet, the indirect effects of ocean acidification on calcifying organisms, which may counter or exacerbate direct effects, is uncertain. Using volcanic CO2 vents, we tested the indirect effects of ocean acidification on a calcifying herbivore (gastropod) within the natural complexity of an ecological system. Contrary to predictions, the abundance of this cal…
Trophic state changes can affect the importance of methane-derived carbon in aquatic food webs
2017
Methane-derived carbon, incorporated by methane-oxidizing bacteria, has been identified as a significant source of carbon in food webs of many lakes. By measuring the stable carbon isotopic composition (δ13C values) of particulate organic matter, Chironomidae andDaphniaspp. and their resting eggs (ephippia), we show that methane-derived carbon presently plays a relevant role in the food web of hypertrophic Lake De Waay, The Netherlands. Sediment geochemistry, diatom analyses and δ13C measurements of chironomid andDaphniaremains in the lake sediments indicate that oligotrophication and re-eutrophication of the lake during the twentieth century had a strong impact on in-lake oxygen availabili…
Tropical Andean forests are highly susceptible to nutrient inputs--rapid effects of experimental N and P addition to an Ecuadorian montane forest.
2012
Tropical regions are facing increasing atmospheric inputs of nutrients, which will have unknown consequences for the structure and functioning of these systems. Here, we show that Neotropical montane rainforests respond rapidly to moderate additions of N (50 kg ha -1 yr -1) and P (10 kg ha -1 yr -1). Monitoring of nutrient fluxes demonstrated that the majority of added nutrients remained in the system, in either soil or vegetation. N and P additions led to not only an increase in foliar N and P concentrations, but also altered soil microbial biomass, standing fine root biomass, stem growth, and litterfall. The different effects suggest that trees are primarily limited by P, whereas some pro…
Controlled feeding experiments with diets of different abrasiveness reveal slow development of mesowear signal in goats ( Capra aegagrus hircus )
2018
ABSTRACT Dental mesowear is applied as a proxy to determine the general diet of mammalian herbivores based on tooth-cusp shape and occlusal relief. Low, blunt cusps are considered typical of grazers and high, sharp cusps typical of browsers. However, how internal or external abrasives impact mesowear, and the time frame the wear signature takes to develop, still need to be explored. Four different pelleted diets of increasing abrasiveness (lucerne, grass, grass and rice husks, and grass, rice husks and sand) were fed to four groups of a total of 28 adult goats in a controlled feeding experiment over a 6-month period. Tooth morphology was captured by medical CT scans at the beginning and end…