Search results for "carbon"
showing 10 items of 6057 documents
Fosildiagénesis del anélido Rotularia spirulaea (Lamarck, 1818) (Polychaeta, Serpulidae) en el Eoceno del dominio pirenaico occidental
2018
The presence of the fossil polychaete Rotularia spirulaea (Lamarck, 1818) in Eocene deposits (middle Lutecian – upper Bartonian and (?) Priabonian) belonging to the western Pyrenean Domain is verified. In this paper, a fossildiagenetic study has been carried out. Fossils from three areas, corresponding to diff erent depositional settings, have been analysed. In area 1, sediments of the Ardanatz Sandstone and Ilundain Marls formations [Pamplona Basin and adjoining areas (Navarre)], were sampled. Here, the specimens of R. spirulaea were not substantially affected by taphonomic reworking and the original microstructure of the carbonate tube is preserved. The test consists of a thick external …
Just transition principles and criteria for food systems and beyond
2022
In this article, we propose a framework of principles and criteria for just transitions in food systems. Climate mitigation activities are urgently needed in food systems, but can have damaging social, environmental, economic, and health impacts. Consequently, food system transitions can cause significant side effects across and beyond food systems, aggravating existing inequalities and unsustainabilities, causing new ones, or hampering equal engagement in the transition itself. Thus, justice questions stand at the core of assessing decarbonization pathways and policies and must link to other sectors as well: Who bears the costs and who enjoys the benefits of the transitions? Can transition…
Stratigraphie séquentielle et architecture sédimentaire haute résolution de l'Oolithe Blanche du Bassin Parisien
2013
La formation carbonatée de l'Oolithe Blanche (Bathonien) du Bassin de Paris est, avec le Trias, un aquifère salin profond majeur qui présente un potentiel réservoir important et reconnu, notamment via l'exploitation géothermique ou les grands projets de recherche dans le domaine du stockage géologique du CO2. Elle a été largement étudiée d'un point de vue sédimentologique et stratigraphique en particulier sur les affleurements de Bourgogne (Floquet et al., 1989 ; Garcia et Sambet, 1994 ; Gaumet et al., 1996 ; Gaumet, 1997). Ces études ont permis de définir un profil de dépôt de type rampe carbonatée qui varie entre une rampe ouverte et une rampe barrée, permettant le développement d'un doma…
Harnessing Molecular Fluorophores in the Carbon Dots Matrix: The Case of Safranin O
2022
The origin of fluorescence in carbon dots (C-dots) is still a puzzling phenomenon. The emission is, in most of the cases, due to molecular fluorophores formed in situ during the synthesis. The carbonization during C-dots processing does not allow, however, a fine control of the properties and makes finding the source of the fluorescence a challenging task. In this work, we present a strategy to embed a pre-formed fluorescent molecule, safranin O dye, into an amorphous carbonaceous dot obtained by citric acid carbonization. The dye is introduced in the melted solution of citric acid and after pyrolysis remains incorporated in a carbonaceous matrix to form red-emitting C-dots that are strongl…
pH and salivary sodium bicarbonate during the administration protocol for methotrexate in children with leukemia
2007
Objective: To analyze the behavior of pH and sodium bicarbonate (NAHCO3) in the saliva of patients with leukemia during the administration protocol for Methotrexate (Mtx). Materials and Methods: A controlled clinical essay was carried out on 23 patients between 4 and 18 years of age with high-risk Acute Lymphoblastic Leukemia. Sampling was carried out at To : basal condition; T1 : 12 hours after intravenous administration of sodium bicarbonate, before administering Mtx and T2 : 3 hours after administering Mtx, the time of maximum concentration. Chiron-Diagnostic 378® equipment was used to determine pH and sodium bicarbonate. The data was interpreted using Analysis of Variance at the 5% sign…
Combined effect of low-molecular-weight organic acids and creosote on phosphatase activities in sandy soil
2018
This paper assesses the impact of creosote and low-molecular-weight organic acids (LMWOAs) on the activity of acid phosphomonoesterase, alkaline phosphomonoesterase, phosphotriesterase, and inorganic pyrophosphatase in soil. The experiment was carried out on loamy sand samples with organic carbon content of 8.71 g · kg -1 , with the following variable factors: dosages of creosote: 0, 0.5%, and 2.5%; type of LMWOAs: oxalic acid, tartaric acid, and citric acid in the amount of 50 mmol · kg -1 of soil; days of experiment: 1, 7, 14, 28, 56, 112. Obtained results showed that contamination with creosote caused decrease in the activity of soil phosphatases. The observed effect did not always incre…
The use of very high resolution images for studying Posidonia oceanica reefs
2020
Posidonia oceanica is an endemic Mediterranean seagrass that forms wide and dense meadows from the surface up to about 40 m depth. This species can develop a biogenic structure called matte, a typical terraced formation built up by itself, consisting of intertwined rhizomes, roots and sediment, which may allow shoots to reach the sea surface forming reefs (récif barrière), considered natural monuments. Posidonia oceanica reefs are particularly exposed to the ongoing increase in temperature and in storm frequency and intensity due to climate change, with negative repercussions on their conservation. Much more attention must be paid to the implementation of monitoring tools able to detect ear…
Sexual selection on song and cuticular hydrocarbons in two distinct populations of Drosophila montana
2011
Sexual selection has the potential to contribute to population divergence and speciation. Most studies of sexual selection in Drosophila have concentrated on a single signaling modality, usually either courtship song or cuticular hydrocarbons (CHCs), which can act as contact pheromones. We have examined the relationship between both signal types and reproductive success using F1–3 offspring of wild- collected flies, raised in the lab. We used two populations of the Holarctic species Drosophila montana that represent different phylogeographic clades that have been separate for ca. 0.5 million years (MY), and differ to some extent in both traits. Here, we characterize the nature and identify …
Grassland fire effect on soil organic carbon reservoirs in semiarid environment.
2011
The effect of fire on soil organic matter content is highly variable and depends on several factors including fire intensity, soil type and nature of burned material. Grassland in semiarid environment are often managed by shepherds with annual burning in order to enhance pasture recovery. The aim of this work was investigating the effect of fire as grassland management tool on soil organic carbon (SOC) reservoirs and on post-fire plant recovery. The study was conducted on Hyparrenia hirta grassland and Ampelodesma mauritanicus grassland, located in the Province of Palermo, in the north of Sicily. Soil samples were collected at two depth (0-5 and 5-20 cm) before and after experimental fire a…
Variazioni di carbonio organico nei suoli italiani dal 1979 al 2008
2010
I suoli contengono circa tre volte la quantità di carbonio disponibile a livello mondiale nella vegetazione e circa il doppio di quella presente in atmosfera. Tuttavia il carbonio organico del suolo (SOC) si è ridotto in molte aree, mentre è stato rilevato un aumento della CO2 atmosferica. Ricerche recenti hanno dimostrato che sono stati i cambiamenti di uso e gestione del suolo a provocare le maggiori perdite di SOC nel recente passato, piuttosto che le più alte temperature e i cambiamenti delle precipitazioni conseguenti il cambiamento climatico. Lo scopo principale di questo lavoro è quello di stimare le variazioni del contenuto di carbonio organico dei suoli (carbon stock, CS) in Italia…