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Keywords: femtosecunde pulze, laser na proste elektrone, Fourier
Published in RUNG: 29.02.2016; Views: 3894; Downloads: 0
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Abstract: We present a catalog of sources detected above 50 GeV by the Fermi-Large Area Telescope (LAT) in 80 months of data. The newly delivered Pass8 event-level analysis allows the detection and characterization of sources in the 50 GeV–2 TeV energy range. In this energy band, Fermi-LAT has detected 360 sources, which constitute the second catalog of hard Fermi-LAT sources (2FHL). The improved angular resolution enables the precise localization of point sources (∼1 7 radius at 68% C.L.) and the detection and characterization of spatially extended sources. We find that 86% of the sources can be associated with counterparts at other wavelengths, of which the majority (75%) are active galactic nuclei and the rest (11%) are Galactic sources. Only 25% of the 2FHL sources have been previously detected by Cherenkov telescopes, implying that the 2FHL provides a reservoir of candidates to be followed up at very high energies. This work closes the energy gap between the observations performed at GeV energies by Fermi-LATon orbit and the observations performed at higher energies by Cherenkov telescopes from the ground.
Keywords: catalogs – gamma-rays
Published in RUNG: 25.02.2016; Views: 5257; Downloads: 0
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Abstract: This study examined the applicability of stable isotope and multi-element data for determining the geographical origin of fresh apple juices. Samples included three apple cultivars (Idared, Golden Delicious and Topaz) harvested in 2011 and 2012 from five different geographical regions of Slovenia. Regional discrimination of the juice samples was most successful when using linear discriminant analysis (LDA) and taking into account the following parameters: d2H and d18O content of juice water; d15N and d13C content of the pulp, (D/H)I and (D/H)II in ethanol and the concentration of S, Cl, Fe, Cu, Zn and Sr. Overall prediction ability was 83.9%. The factors that best distinguished the different types of cultivar were the d2H and d18O content of fruit juice water; the d13C and (D/H)I content of ethanol; and the concentration of S, Mg, K, Cu, and Ti. Prediction ability, taking into account all ten parameters, was 75.8%.
Keywords: Apple juice, Stable isotopes, Elemental content, Geographical origin, Slovenia
Published in RUNG: 15.02.2016; Views: 6078; Downloads: 0
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Abstract: In the past years, several studies have revealed the presence of organic contaminants at concentrations from sub ng g–1 to mg g–1 on/in plastic pellets found in coastal environment worldwide [1,2,3]. Plastic pellets are actually industrial raw material, typically in the shape of small granules with a diameter of a few mm. They are categorized as microplastics (< 5 mm). They can be unintentionally lost in the environment during manufacturing and transport. They can subsequently reach the marine and coastal compartments. Due to their environmental persistence, they are widely distributed in the oceans and on beaches [1]. Organic pollutants associated to pellets are either additives (e.g. PBDEs) that are incorporated into plastics during production processes or hydrophobic chemicals (e.g. PCBs, organochlorine pesticides) which adsorb from the surrounding environment (e.g. seawater). Among these chemicals, some are recognized as POPs (Persistent Organic Pollutants) because of their persistence, bioaccumulation and potential adverse environmental and health effects. Thus, in order to better assess the impact of plastic pellets in coastal environment, it is necessary to determine the level of associated organic pollutants. The present study was carried out in the frame of DeFishGear project, which focuses on marine litter and microplastics issues in Adriatic region. This investigation aimed at developing an experimental protocol allowing the quantification of 11 organochlorine pesticides. Plastic pellets, sampled on beaches located in the Adriatic region, were first sorted by colour. Pesticides were extracted from the plastic matrix (c.a. 0.5 g) in a pressurized fluid extractor (50°C, 100 bar). Prior to evaporation, the extract was cleaned on Florisil sorbent through solid-phase extraction (SPE). The concentrated extracts were quantified on gas chromatography equipped with a micro electron capture detector (GC-μECD). Preliminary results revealed the presence of DDT transformation products.
Keywords: organochlorine pesticides, microplastics, pellets, Adriatic region
Published in RUNG: 15.02.2016; Views: 4765; Downloads: 0
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Abstract: Saccharomyces cerevisiae and its sibling species S. paradoxus are known to inhabit temperate arboreal habitats across the globe. Despite their sympatric distribution in the wild, S. cerevisiae is predominantly associated with human fermentations. The apparent ecological differentiation of these species is particularly striking in Europe where S. paradoxus is abundant in forests and S. cerevisiae is abundant in vineyards. However, ecological differences may be confounded with geographic differences in species abundance. To compare the distribution and abundance of these two species we isolated Saccharomyces strains from over 1,200 samples taken from vineyard and forest habitats in Slovenia. We isolated numerous strains of S. cerevisiae and S. paradoxus as well as small number of S. kudriavzevii strains from both vineyard and forest environments. We find S. cerevisiae less abundant than S. paradoxus on oak trees both within and outside the vineyard, but more abundant on grapevines and associated substrates. Analysis of the uncultured microbiome shows that both S. cerevisiae and S. paradoxus are rare species in soil and bark samples, but can be much more common in grape must. In contrast to S. paradoxus, European strains of S. cerevisiae have acquired multiple traits thought to be important for life in the vineyard and dominance of wine fermentations. We conclude that S. cerevisiae and S. paradoxus currently share both vineyard and non-vineyard habitats in Slovenia and we discuss factors relevant to their global distribution and relative abundance.
Keywords: Wine, microbiome, yeast, Ecology, Fermentation
Published in RUNG: 12.02.2016; Views: 5800; Downloads: 200
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