269 research outputs found
Priprava nekoliko novih piridina, tienopiridina i pirido[2,3:4\u27,5\u27]tieno[3\u27,2\u27-d]pirimidin-8-ona iz 2-acetilbenzoimidazola
Reaction of 2-acetylbenzoimidazole 1 with some arylaldehydes under different conditions gave chalcones, 1,5-pentanediones and pyridines. Treatment of chalcones with various types of reagents gave the corresponding new pyridines, thienopyridines, pyrido[2,3:4\u27,5\u27]thieno[3\u27,2\u27-d]- pyrimidin-8-ones via initial addition of active methylene or amino group to the double bond followed by cyclization.Reakcija 2-acetilbenzoimidazola s nekim arilaldehidima pod razli~itim uvjetima daje halkon, 1,5-pentandione i piridine. Obrada halkona s razli~itim reagensima daje nove piridine, tienopiridine i pirido[2,3:4\u27,5\u27]ti -eno[3\u27,2\u27-d]pirimidin-8-one preko po~etne adicije metilena ili amino grupe na dvostruku vezu i nakon toga slijedi
ciklizacija
Recent turbidite deposition in the eastern Atlantic: Early diagenesis and biotic recovery
An interface core taken in Capbreton canyon shows a succession of sedimentary facies interpreted as classical Bouma turbiditic sequences. Activities of 234Th and 210Pb suggest that the deposition of the most recent turbidite was triggered by the violent storm that affected the Atlantic coast of southern France on the 27th of December 1999, about four months before the sampling of the core. This turbidite allows us to study the ongoing diagenesis of the new sediment layer and of the previous sediment-water interface, which has been buried and only slightly eroded. A study of benthic foraminiferal populations informs us about the rate of benthic ecosystem recovery after such a major ecosystem disturbance event. The composition of the benthic foraminiferal fauna suggests that the benthic ecosystem in Capbreton canyon remains in an early stage of colonization. The rare agglutinant taxon Technitella melo appears to be the first colonizing species. It is suggested that Technitella melo is advantaged by the food-impoverished conditions in the days following turbidite deposition. Almost all of the turbidite layer and the previous oxic sediment-water interface contain reduced dissolved metal species and were anoxic. The buried interface contains Fe- and Mn-oxides inherited from its recent oxic past. The reduction of manganese oxides was in progress at the time of core collection. The reduced Mn remained trapped in the sediment as Mn-containing carbonates. Iron-oxides did not undergo significant reductive dissolution. The top of the newly deposited turbidite formed an oxic layer, which was rapidly enriched in metal-oxides. The enrichment of manganese oxides was mostly due to the oxidation of dissolved Mn2+, which diffused from below. The enrichment of iron oxides is explained both by the oxidation of the upward flux of dissolved Fe2+, and by the input of detrital iron oxide after, or as a result of the turbidite deposition
Characterization of Inertial Electrostatic Confinement Fusion Plasma Device
Inetial electrostatic confinment fusion (IECF) device constructed at the Egyptian Atomic Energy Authority (EAEA-IEC), is introduced the characterization of the IEC plasma device. The x-ray and visible light emissions in IEC plasma device were investigated by employing time -resolved detector and measure of the total amount of visible light using lux meter
People and climate: holocene sediment records of environmental change in Middle Egypt: fieldwork report and initial results
The aim of this project is to reveal more about the history of Lake Qarun through a multidisciplinary environmental study. This approach primarily concerns the examination of sediment
records, but also includes collection of data from archaeological sites in the Faiyum. The sedimentary
history of Lake Qarun will be compared with (i) independent palaeoclimate records for the East
African Highlands and the eastern Mediterranean; (ii) local evidence (including Nile alluvial and
palaeo-shoreline sequences and Holocene playa deposits); and (iii) the cultural history of the Faiyum.
This report describes the fieldwork performed to obtain long sediment cores for palaeolimnological
analysis and presents initial results from those cores. Results will be used to construct a Geographical
Information System (GIS)
Narghile (water pipe) smoking among university students in Jordan: prevalence, pattern and beliefs
<p>Abstract</p> <p>Background and objectives</p> <p>Narghile is becoming the favorite form of tobacco use by youth globally. This problem has received more attention in recent years. The aim of this study was to investigate the prevalence and pattern of narghile use among students in three public Jordanian universities; to assess their beliefs about narghile's adverse health consequences; and to evaluate their awareness of oral health and oral hygiene.</p> <p>Methods</p> <p>The study was a cross-sectional survey of university students. A self-administered, anonymous questionnaire was distributed randomly to university students in three public Jordanian universities during December, 2008. The questionnaire was designed to ask specific questions that are related to smoking in general, and to narghile smoking in specific. There were also questions about oral health awareness and oral hygiene practices.</p> <p>Results</p> <p>36.8% of the surveyed sample indicated they were smokers comprising 61.9% of the male students and 10.7% of the female students in the study sample. Cigarettes and narghile were the preferred smoking methods among male students (42%). On the other hand, female students preferred narghile only (53%). Parental smoking status but not their educational level was associated with the students smoking status. Smokers had also significantly poor dental attendance and poor oral hygiene habits.</p> <p>Conclusion</p> <p>This study confirmed the spreading narghile epidemic among young people in Jordan like the neighboring countries of the Eastern Mediterranean region. Alarming signs were the poor oral health awareness among students particularly smokers.</p
Temperature calibration of Mg/Ca ratios in the intermediate water benthic foraminifer Hyalinea balthica
Author Posting. © American Geophysical Union, 2011. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry Geophysics Geosystems 12 (2011): Q04003, doi:10.1029/2010GC003333.Core top samples from Indonesian and northeast Atlantic depth transects were used to calibrate Mg/Ca and δ18O in tests of the calcitic benthic foraminifer Hyalinea balthica to bottom water temperature between 4°C and 13°C. This shallow infaunal species is primarily abundant in neritic to upper bathyal sediments (<600 m). Both linear and exponential calibrations suggest a temperature sensitivity of ~12% per °C that is ~4 times higher than observed in other species of deep-sea benthic foraminifera. Culture experiments support the core top calibration. We find no discernible effect of salinity and saturation on Mg/Ca. Comparison between the measured benthic foraminiferal δ18O and predicted equilibrium values suggests that on average H. balthica δ18O is 0.64‰ ± 0.13‰ lower than predicted from the equilibrium composition. To test the reliability of using paired H. balthica Mg/Ca and δ18O measurements for reconstructing seawater δ18Osw and salinity, we apply this calibration to another depth transect from Cape Ghir off NW Africa, which was not included in the calibration. Based on error analysis of the calibration data and this validation test, we show that the uncertainty of reconstructing bottom water temperature and salinity from paired Mg/Ca and δ18O measurements of H. balthica is better than ±0.7°C and ±0.69 practical salinity scale, respectively. The small uncertainties allow for the reconstruction of seawater density to better than 0.3σθ units, which is precise enough for the identification of specific water masses and reconstruction of changes in their properties. We propose that the relatively high Mg content and temperature sensitivity of H. balthica might be due to minor, biologically mediated contribution of high-Mg calcite to the primarily low Mg calcite test, which is influenced by the ambient temperature. This hypothesis, if correct, suggests that benthic species with relatively high Mg/Ca may be better suited for deepwater temperature reconstructions than species that have thus far been more commonly used.This project
was funded by NSF Awards OCE 02‐20922 and 09‐02977 to
YR, OCE 09‐28607 to MK, OCE02‐20776 to DWO, and DFG
priority program INTERDYNAMIK to AM
Co3O4 nanoparticles as oxygen carriers for chemical looping combustion: A materials characterization approach to understanding oxygen carrier performance
Using sewage sludge as a sealing layer to remediate sulphidic mine tailings: a pilot-scale experiment, northern Sweden
Hyperspectral remote sensing to assess the water status, biomass, and yield of maize cultivars under salinity and water stress
Gold supported on CuOx/CeO2 catalyst for the purification of hydrogen by the CO preferential oxidation reaction (PROX)
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