Search results for "carbon"

Body size and population dynamics of enchytraeids with different disturbance histories and nutrient dynamics

2010

The population dynamics of the enchytraeid Cognettia sphagnetorum originating from an unmanaged forest (FP), a clear-cut area (CCP) or a plot treated with birch ash (APP) and the effects of population origin on labile C and N dynamics were investigated. Twenty individuals of C. sphagnetorum were introduced in microcosms containing humus from the unmanaged forest devoid of enchytraeids and amended with sucrose, and incubated for 14 weeks. Triplicate microcosms from FP, CCP and APP treatments were destructively sampled every second week and enchytraeid population density, individual length, nematode abundance and trophic structure, humus properties and dissolved organic C (DOC) and N (DON), a…

The analysis of methods for measurement of methane oxidation in landfills

2003

Landfills and dumps are important sources of atmospheric methane. There is no generally accepted estimate of the influence of methane oxidation on landfill methane emissions. The present work aimed to analyse different methods for the investigation of methane emission and oxidation in methane-producing environments (wetlands, landfills, sludge checks), and to develop the precise procedure for the landfills. The combination of geochemical and microbiological methods to estimate and monitor the oxidation and emission of methane in landfills during different seasons is proposed. It includes the measurements, both on the surface and at different depths (up to 1 m) of landfill ground of the foll…

ChemInform Abstract: Theoretical and Spectroscopic Studies on Imino-Carbon Palladated Pyridine-2-carbaldimines.

1987

Abstract Ab initio LCAO-MO-SCF calculations on the model compounds C 5 H 4 N-2-C(R 1 )=NH [R 1 = H ( 2c ) and R 1 = trans -PdCl(PH 3 ) 2 ( 4c )] indicate that the E - trans conformation is favored over the E - cis one by 16.9 kJ mol −1 for 2c and by 25.0 kJ mol −1 for 4c . One of the factors which stabilizes the E-trans arrangement for 4c is a weak bonding interaction between the palladium center and the pyridine nitrogen. On going from 2c to 4c a slight charge enrichment on the pyridine carbons and a more pronounced one on the nitrogen atoms is computed, whereas the charge density of the imino carbon atom is decreased. In 4c no π contribution to the PdC bond is observed. Protonation of th…

Influence of Bond Fixation in Benzo-Annulated N-Salicylideneanilines and Their ortho-C(O)X Derivatives (X = CH3, NH2, OCH3) on Tautomeric Equilibria …

2007

1H, 13C, and 15N NMR spectra show that an ortho-C(=O)X group present in the molecules of N-salicylideneanthranilamide (X = NH2), methyl N-salicylideneanthranilate (X = OCH3), N-salicylidene-o-aminoacetophenone (X = CH3), and their benzo analogues have only a minor effect on the tautomeric OH/NH-equilibrium in solution. Only two of three possible tautomers were detected. Lability of the absent form was proved by theoretical calculations. Calculated energies show that the enolimino form (OH) is less stable than the enaminone (NH) form only for dibenzo-annulated N-salicylideneanilines. The population of each species in the tautomeric mixture was found to be inversely proportional to its energy…

Emersion generalisee intra-maastrichtienne de la plate-forme de Gavrovo-Tripolitza (Grece); effets sur les populations de foraminiferes Rhapydioninin…

2001

Abstract The reliability of biostratigraphic correlations in neritic carbonate platforms is often questioned because the benthic fauna on which biozonation is based are particularly sensitive to environmental change. It is crucial to know whether a population change corresponds strictly to a facies change. Conversely, there arise the questions of determining how populations are renewed over time and how new species appear even if facies associations remain unchanged. This is the case with the Gavrovo-Tripolitza zone of Greece, an isolated shallow carbonate platform surrounded by two oceanic domains (Pindos-Olonos Zone and Ionian Zone). The absence or scarcity of faunas generally used in Upp…

Role of the aryl hydrocarbon receptor (AhR) signaling pathway in exceptional longevity in humans

2018

Centenarians are the best example of successfully aging in humans. Thus, the characterization of the biological processes and pathways in this population is an excellent strategy to understand the lifespan extension. The aryl hydrocarbon receptor (AhR) is a ligand-activated-transcription factor historically known for regulating expression of several important drug-detoxifying proteins. But recently its role in the immune response and in cellular homeostasis has been recognized. Furthermore, AhR is activated in C. Elegans in extreme longevity due to a dietary restriction. We report here results of a whole transcriptome analysis of centenarians. The main biological process was the immune resp…

Measurements on electric breakdown in dielectric barriers between carbon nanotubes and electrodes

2009

Synthesis of cyanoacetic acid by electrocatalytic carboxylation of chloroacetonitrile at a silver cathode

2008

Electrochemical conversion of Carbon Dioxide: effect of operating parameters and of the reactor on the performances of the process.

2017

Gas phase behavior of radical cations of perfluoroalkyl-1,2,4-triazines: an experimental and theoretical study

2009

Electron ionization mass spectrometry and low-energy collision-induced decomposition reactions occurring in a tridimensional ion trap, together with density functional theory (DFT) calculations on neutrals, even- and odd-electron cations, have been used to study the gas-phase ion chemistry of a series of perfluoroalkyl-1,2,4-triazines. Loss of oxygen, due to thermal degradation occurring before ionization, likely involving the hydroxylamino group, has been observed. Compounds having a carbonyl group at position 6 of the triazine ring fragment in the source by elimination of NO followed by HF or CO. The decomposition pathways occurring due to CID experiments have shown interesting features d…