Ovisnost nuklearne prozirnosti o Q2 za nekoherentnu elektrotvorbu ρ0

Measurements of exclusive incoherent electroproduction of ρ0 (770) meson from 2H, 12C, and 63Cu targets up to Q2 = 4 GeV2 are proposed using the CLAS detector at Jefferson Lab. The objective of these measurements is to determine the Q2 dependence of the nuclear transparency ratio for the two nuclear targets: 12C and 63Cu at fixed coherence length of quark-antiquark fluctuations of the virtual photon. A sizeable rise of the nuclear transparency is predicted and can be measured in this experiment. A relatively large increase of the nuclear transparency can be considered as a signature of the onset of color transparency.Predlažemo mjerenja ekskluzivne elektrotvorbe ρ0 (770) mezona u metama 2H, 12C i 63Cu, za Q2 = 4 GeV2 , pomoću detektora CLAS u Jeffersonovom Labu. Cilj mjerenja je određivanje nuklearne prozirnosti u ovisnosti o Q2 za dvije nuklearne mete, 12C i 63Cu, pri određenoj koherentnoj duljini fluktuacija kvark-antikvark virtualnog fotona. Predviđa se znatno povećanje nuklearne prozirnosti koje se može mjeriti u predloženom eksperimentu. Znatan porast nuklearne prozirnosti bi se smatrao znakom za pojavu prozirnosti boje

Structural changes in lipid-free humic acids during composting of sewage sludge

Structural changes in humic acids (HAs), extracted after lipid removal from sewage sludge during composting, were investigated using various chemical methods (elemental analysis, Fourier transform infrared spectroscopy and 13C-nuclear magnetic resonance (NMR) spectroscopy). Compared to non-purified HAs, lipid-free HAs (LFHAs) exhibit higher C and N contents and high absorbance around 1652, 1540 and 1230 cm1, which indicates the intensity of the etherified aromatic structures and nitrogencontaining components. Less absorbance around 2920, 1600, 1414 and 1100 cm1 could be assigned to their low level of aliphatic compounds, mainly those with a carboxyl group. According to 13C-NMR spectroscopy, almost 45% of aliphatic structures are removed by lipid extraction and these correspond mainly to long-chain fatty acids. During composting, significant decomposition of non-substituted alkyl structures and N-containing components occurred, increasing the relative intensity of etherified aromatic structures

Ovisnost nuklearne prozirnosti o Q2 za nekoherentnu elektrotvorbu ρ0

Measurements of exclusive incoherent electroproduction of ρ0 (770) meson from 2H, 12C, and 63Cu targets up to Q2 = 4 GeV2 are proposed using the CLAS detector at Jefferson Lab. The objective of these measurements is to determine the Q2 dependence of the nuclear transparency ratio for the two nuclear targets: 12C and 63Cu at fixed coherence length of quark-antiquark fluctuations of the virtual photon. A sizeable rise of the nuclear transparency is predicted and can be measured in this experiment. A relatively large increase of the nuclear transparency can be considered as a signature of the onset of color transparency.Predlažemo mjerenja ekskluzivne elektrotvorbe ρ0 (770) mezona u metama 2H, 12C i 63Cu, za Q2 = 4 GeV2 , pomoću detektora CLAS u Jeffersonovom Labu. Cilj mjerenja je određivanje nuklearne prozirnosti u ovisnosti o Q2 za dvije nuklearne mete, 12C i 63Cu, pri određenoj koherentnoj duljini fluktuacija kvark-antikvark virtualnog fotona. Predviđa se znatno povećanje nuklearne prozirnosti koje se može mjeriti u predloženom eksperimentu. Znatan porast nuklearne prozirnosti bi se smatrao znakom za pojavu prozirnosti boje

Detailed study of Brazil nut (Bertholletia excelsa) oil micro-compounds : Phospholipids, tocopherols and sterols

The oil of the Brazil nut (Bertholletia excelsa) was studied for its composition in fatty acids, tocopherols, sterols and phospholipids. The fatty acids composition of phospholipids was also studied. These results were compared to those of sunflower, walnut, almond, soya and olive oils. Its high content of unsaturated fatty acids, of [bêta]-tocopherol and of [bêta]-sitosterol gave to the Brazil nut interesting antioxidant and anti-cholesterol properties. The composition of fatty acids in phospholipid is very different from the composition of the oil. Linolenic acid, which is not present in the oil, is present at a high level in phosphatidylethanolamine. (Résumé d'auteur

Microbial community dynamics during composting of sewage sludge and straw studied through phospholipid and neutral lipid analysis

The composting process involves a succession of different communities of microorganisms that decompose the initial material, transforming it into a stable final product. In thiswork, the levels of phospholipid fatty acid (PLFA), neutral lipid fatty acid (NLFA) and sterolwere monitored in compost versus time, as indicators of the activity of various microorganisms (Gram-positive or Gram-negative bacteria, fungi, etc.). During composting, the PLFA and NLFA from Gram-negative bacteria and eukaryotes (2-OH 10; 3-OH 12; 2-OH 14; 13:0; 16:1; 18:1 trans) aswell as some sterols of plant origin (e.g. monostearin sterols) decreased until the end of composting. In contrast, the branched fatty acids with iso- and anteiso-forms (i-15:0; a-15:0; i-16; i-17) increased mainly in the thermophilic phase, but decreased right after. The PLFA 18:2 (6;9), which is used as an index of the occurrence of some fungi, rose strongly at the beginning of composting, but fell after peak heating. In contrast, the other main sterol indicative of fungi, ergosterol, decreased at the beginning of the thermophilic phase, but increased strongly by the end of composting. Accordingly, cluster and PCA analysis separated the PLFA of Gram-negative bacteria and eukaryotic cells from those of Gram-positive bacteria and long-chain fatty acids. The fungal PLFA considered, 18:2 (9, 12), was clustered more closely to iso- and anteiso-branched PLFAs. Stigmasterol, squalene and cholesterol occurred in the lower right part of the loading plot and were clustered more closely to iso-, anteiso-branched PLFAs and 18:2w6,9 suggesting their relationship to microbial activities. We also observed the tendency of resistance of fatty acid PLFAs and NLFAs of long chain (19:0 (cis-9); 20:0) and some recalcitrant sterols, e.g. sitosterol, at the end of composting. The presence of high levels of the latter in the final stage indicates their contribution to the structural stability of organic matter fractions. These recalcitrant components were more clustered and occurred in the lower right part of the loading plot