Properties of Reactive Oxygen Species by Quantum Monte Carlo

The electronic properties of the oxygen molecule, in its singlet and triplet states, and of many small oxygen-containing radicals and anions have important roles in different fields of Chemistry, Biology and Atmospheric Science. Nevertheless, the electronic structure of such species is a challenge for ab-initio computational approaches because of the difficulties to correctly describe the statical and dynamical correlation effects in presence of one or more unpaired electrons. Only the highest-level quantum chemical approaches can yield reliable characterizations of their molecular properties, such as binding energies, equilibrium structures, molecular vibrations, charge distribution and polarizabilities. In this work we use the variational Monte Carlo (VMC) and the lattice regularized Monte Carlo (LRDMC) methods to investigate the equilibrium geometries and molecular properties of oxygen and oxygen reactive species. Quantum Monte Carlo methods are used in combination with the Jastrow Antisymmetrized Geminal Power (JAGP) wave function ansatz, which has been recently shown to effectively describe the statical and dynamical correlation of different molecular systems. In particular we have studied the oxygen molecule, the superoxide anion, the nitric oxide radical and anion, the hydroxyl and hydroperoxyl radicals and their corresponding anions, and the hydrotrioxyl radical. Overall, the methodology was able to correctly describe the geometrical and electronic properties of these systems, through compact but fully-optimised basis sets and with a computational cost which scales as $N^3-N^4$, where $N$ is the number of electrons. This work is therefore opening the way to the accurate study of the energetics and of the reactivity of large and complex oxygen species by first principles

The flora of Istria: Juncaceae

A checklist, key and distribution were prepared for the Juncaceae family after research into the Istrian flora was completed. According to the checklist, the Juncaceae family in Istria includes two genera (Juncus and Luzula) and 27 taxa (species, subspecies and varieties). During research in 2003 and 2004, two new taxa were discovered in the Istrian flora: Juncus hybridus Brot. in ephemeral and wet locations along the Premantura Peninsula and Juncus littoralis C.A. Mey ssp. tommasinii (Parl.) Arcang. at the mouth of the Raša River

Schoenus nigricans (Cyperaceae) xerophytic grasslands on the NE Adriatic islands Cres and Krk (Croatia)

Several xerophytic grasslands on the NE Adriatic islands Cres and Krk (Croatia) are dominated by tussock-forming Schoenus nigricans (Cyperaceae). All vegetation types reported are characterised by the degradation of the vegetation cover due to grazing. Phytosociologically, the vegetation is classified as the Danthonio-Scorzoneretum villosae subass. schoenetosum nigricantis H-i} 57 of the Scorzonerion villosae H-i} 49 alliance within the order Scorzonero-Chrysopogonetalia, but partly shows transitions to the Bromo-Chrysopogonetum grylli H-i} 60.We differentiated three variants: more xerophytic sites (on Cres), sites characterised by alternating soil humidity (mainly on Krk), and advanced succession stages. Physiognomically all variants are dominated by Schoenus nigricans tussocks, which are fostered by sheep grazing and the summer-dry conditions on the compacted soils. Comparison with Central European more humid habitats suggests the hypothesis of an ecotypic differentiation of Schoenus nigricans within its European distribution area

Elevation correction of ERA-Interim temperature data in complex terrain

Air temperature controls a large variety of environmental processes, and is an essential input parameter for land surface models, for example in hydrology, ecology and climatology. However, meteorological networks, which can provide the necessary information, are commonly sparse in complex terrains, especially in high mountainous regions. In order to provide temperature data in an adequate temporal and spatial resolution for local scale applications a new elevation correction method has been developed that is able to downscale 3-hourly ERA-Interim temperature data. The scheme is based on model internal vertical lapse rates derived from different ERA-Interim pressure levels and has been validated for twelve meteorological stations in the German and Swiss Alps. The method was also compared with two other statistical, lapse rate based correction approaches. The results indicate that the use of model internal ERA-Interim lapse rates can significantly improve the downscaling performance when compared to the standard procedure of using fixed lapse rates

Sources of variability in essential oil composition of Ocimum americanum and Ocimum tenuiflorum

Basil has traditionally been used for a long time in medicine and gastronomy. Essential oil is the most important active substance of the drug, which influences the aroma and the effect of the plant. Although the compositions of essential oils vary in different basil cultivars, the main components are oxygenated monoterpenes and phenylpropane derivates. The high chemical variation is most likely caused by interspecific hybridization. Various factors, like genetic background, ontogenesis, morphogenesis, abiotic factors, essential oil extraction method, drying, and storage, are responsible for the variant essential oil composition

Sneutrino LSPs in R-parity violating minimal supergravity models

We consider the minimal supergravity model (mSUGRA) with one additional R-parity violating operator at the GUT scale. The superparticles mass spectra at the weak scale are generally altered due to the presence of the R-parity violating coupling in the renormalization group equations. We show that a lepton number violating coupling at the GUT scale can lead to a sneutrino as the lightest supersymmetric particle (LSP) in a large region of parameter space consistent with the muon anomalous magnetic moment and other precision measurements. We also give characteristic collider signatures at the LHC.Comment: 3 pages, 3 figures, to appear in the proceedings of SUSY08, Seoul, Kore

Identification of catchment functional units by time series of thermal remote sensing images

The identification of catchment functional behavior with regards to water and energy balance is an important step during the parameterization of land surface models. An approach based on time series of thermal infrared (TIR) data from remote sensing is developed and investigated to identify land surface functioning as is represented in the temporal dynamics of land surface temperature (LST). For the mesoscale Attert catchment in midwestern Luxembourg, a time series of 28 TIR images from ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) was extracted and analyzed, applying a novel process chain. First, the application of mathematical-statistical pattern analysis techniques demonstrated a strong degree of pattern persistency in the data. Dominant LST patterns over a period of 12 years were then extracted by a principal component analysis. Component values of the two most dominant components could be related for each land surface pixel to land use data and geology, respectively. The application of a data condensation technique ("binary words") extracting distinct differences in the LST dynamics allowed the separation into landscape units that show similar behavior under radiationdriven conditions. It is further outlined that both information component values from principal component analysis (PCA),as well as the functional units from the binary words classification, will highly improve the conceptualization and parameterization of land surface models and the planning of observational networks within a catchment

Sneutrino as Lightest Supersymmetric Particle in B3 mSUGRA Models and Signals at the LHC

We consider B3 mSUGRA models where we have one lepton number violating LQD operator at the GUT scale. This can alter the supersymmetric mass spectrum leading to a sneutrino as the lightest supersymmetric particle in a large region of parameter space. We take into account the restrictions from neutrino masses, the muon anomalous magnetic moment, b -> s gamma and other precision measurements. We furthermore investigate existing restrictions from direct searches at LEP, the Tevatron and the CERN p\bar p collider. We then give examples for characteristic signatures at the LHC.Comment: 22 pages, 11 figure

N-ACETYLCYSTEINE REVERSES LATE GESTATIONAL STRESS INDUCED MATERNAL OXIDATIVE DAMAGE

Objective: This study was intended to investigate the effect of early and late gestational stress, on the levels of antioxidants and antioxidant enzymes in maternal serum that reflects oxidative damage. We also aimed at evaluating the protective role of N-acetylcysteine (NAC) against this oxidative stress. This study was carried out with speculation in mind that maternal oxidative damage could be the cause for developmental defects in off spring.Methods: Pregnant rats were exposed to restrain stress thrice daily, either during the first half or during the second half of gestation. Other groups were treated with N-acetylcysteine throughout pregnancy, along with exposure to either early gestational stress or late gestational stress. Control group was kept undisturbed throughout pregnancy. Immediately after delivery, blood was drawn to estimate the serum antioxidant levels.Results: Pregnant rats exposed to stress during the late gestational period showed significant variation in the level of serum MDA, Glutathione Reductase, reduced glutathione, SOD and total antioxidant capacity although, administration of NAC brought about improvement in the antioxidant status.Conclusion: NAC is an effective antioxidant that can bring down the oxidative damage caused by late gestational stress in rats.Â