Search results for "Nitrogen"

Short-term effect of ammonia concentration and salinity on activity of ammonia oxidizing bacteria.

2010

A continuously aerated SHARON (single reactor high activity ammonia removal over nitrite) system has been operated to achieve partial nitritation. Two sets of batch experiments were carried out to study the effect of ammonia concentration and salinity on the activity of ammonia-oxidizing bacteria (AOB). Activity of AOB raised as free ammonia concentration was increased reaching its maximum value at 4.5 mg NH 3 -N l −1 . The half saturation constant for free ammonia was determined (K NH 3 = 0.32 mg NH 3 -N l −1 ). Activity decreased at TAN (total ammonium–nitrogen) concentration over 2,000 mg NH 4 -N l −1 . No free ammonia inhibition was detected. The effect of salinity was studied by adding…

Novel Glutamate–Putrescine Ligase Activity in Haloferax mediterranei: A New Function for glnA-2 Gene

2021

This article belongs to the Section Cellular Biochemistry.

4-(3H)-quinazolinones N-3 substituted with a five membered heterocycle: A promising scaffold towards bioactive molecules

2020

Abstract The quinazolinone nucleus represents, among the class of fused heterocycles, a very important scaffold to obtain molecules with biological activities. A review of literature revealed how such kind of fused heterocycles, coming from natural or synthetic source, are associated with a wide range of biological activities. This review is mainly directed towards the 4-(3H)-quinazolinones N-3 substituted with a five membered heterocycle in which all the possible combinations of nitrogen, sulfur and oxygen atoms are present.

Origin and Diet of the Prehistoric Hunter-Gatherers on the Mediterranean Island of Favignana (Ègadi Islands, Sicily)

2012

Hunter-gatherers living in Europe during the transition from the late Pleistocene to the Holocene intensified food acquisition by broadening the range of resources exploited to include marine taxa. However, little is known on the nature of this dietary change in the Mediterranean Basin. A key area to investigate this issue is the archipelago of the Ègadi Islands, most of which were connected to Sicily until the early Holocene. The site of Grotta d'Oriente, on the present-day island of Favignana, was occupied by hunter-gatherers when Postglacial environmental changes were taking place (14,000-7,500 cal BP). Here we present the results of AMS radiocarbon dating, palaeogenetic and isotopic ana…

Luminescence spectra and decay kinetics in ZnWO4 and CdWO4 crystals

2004

The luminescence spectra and luminescence decay kinetics in ZnWO4 (nominal pure and doped with Fe and Mo) under pulsed electron beam and pulsed nitrogen laser excitation have been investigated. It is suggested that the two-stage intrinsic luminescence decay observed under ionizing radiation excitation in ZnWO4 and CdWO4 was due to two different self-trapped exciton (STE) configurations in these crystals. The role of Fe and Mo impurities for scintillation efficiency in ZnWO4 and CdWO4 has been discussed. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

THE EFFECT OF ROOTS CONFINEMENT ON THE RELATIVE GROWTH OF ROOTS AND CANOPY OF OPUNTIA FICUS-INDICA

Summary The influence of soil volume on roots and canopy growth performance of cactus pear (Opuntia ficus-indica) was studied at Palermo University. In November 2014, 1-year-old Opuntia ficusindica cladodes were planted in five different volumes of soil 50, 33, 18, 9 and 5 Liters. Three replicates (plants) per pot size were dug out at 6 and 12, 18 and 24 month intervals, thus in total, there were 5 x 3 x 4= 60 experimental plots. The resulting experimental design was a completely randomized design with combinations of two factors, soil volume and month of the sampling, with three replications. Roots of each plant were washed and visually divided into three groups depending on their diameter…

Spatial variability of ecophysiological performances and invasive potential of alien acacias (Acacia spp.) in Sicily and Lampedusa island (Pelagie Ar…

2012

Acacia spp. are among the most widespread and prominent invaders within Mediterranean-type ecosystems, where have already shown the capability to deeply change the characters and the functioning of invaded ecosystems (like in Portugal or S Africa: e.g. Holmes & Cowling, 1997; Hellmann et al., 2011). In Sicily, just in the last few years, two Australian Acacias, notably Acacia cylops A. Cunn. ex G. Don and A. saligna (Labill.) H.L.Wendl., started to regenerate abundantly within different areas (especially afforested sites). However their naturalization process has not been studied up to now.

Effect of Afforestation on Soil Carbon and Nitrogen Content on a Mediterranean Island (Lampedusa, Italy)

2015

During the 20th century, large surfaces in the Mediterranean countries were subject to afforestation activities, mostly affecting abandoned agricultural lands. Under semi-arid climate conditions, Pinus spp. were the most frequently used species for these activities. The effect of pine plantations on soil organic carbon (SOC) and nitrogen (N) content in Lampedusa Island (South Italy) was investigated. SOC and soil N content under pine plantations of different ages (14, 24 and 43 years since plantation) were compared with SOC and soil N content in garrigue communities, which were dominated by shrubs, subshrubs and perennial herbs. The results showed that SOC content is affected by plantation …

Stable isotope analysis of trophic niche in two co-occurring native and invasive terrapins, Emys orbicularis and Trachemys scripta elegans

2016

A trophic niche overlap in native and alien turtle species can lead to competitive interactions whereby allochthonous turtles may outcompete autochthonous individuals and eventually affect viability of natural populations. The European pond turtle (Emys orbicularis) is an autochthonous species threatened by habitat encroachment and competition with the red-eared slider (Trachemys scripta elegans). The latter is an invasive species introduced in Europe from midwestern United States as a pet and now widespread in the natural habitats of E. orbicularis. The extent of trophic competition between E. orbicularis and T. s. elegans in northern Italy was assessed by nitrogen and carbon stable isotop…

Decomposition rate and invertebrate colonization of seagrass detritus along a hydrodynamic gradient in a Mediterranean coastal basin: The Stagnone di…

2019

International audience; Seagrass leaf litter decomposition is a key component of marine carbon flow driven by both biotic and abiotic factors, including water movement. In this study, we analyse Posidonia oceanica litter decomposition and invertebrate colonization in three sites with different hydrodynamics in a coastal basin. Litterbags were put on the sea bed along a gradient of distance from the open sea, implying a different level of water exchange. Leaf litter mass loss and carbon and nitrogen concentration were analysed, and density and biomass of benthic invertebrates colonizing litterbags were recorded after 3, 7, 14, 47, 101, 152 and 221 days. Results showed that in the most shelte…