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1.
The impact of gravel extraction on hyporheic ecology: a case study of the Bača river (W Slovenia)
Nataša Mori, 2008, doctoral dissertation

Found in: ključnih besedah
Summary of found: ...river, hyporheic biota, benthic organisms, particulate organic matter, POM, fine sediment, ETS activity, electron transport...
Keywords: hyporheic invertebrate, Soča river, Bača river, hyporheic biota, benthic organisms, particulate organic matter, POM, fine sediment, ETS activity, electron transport system, sediments, Nematoda, Harpacticoida, Chironomidae, gravel extraction, environmental impact assessment
Published: 19.02.2015; Views: 2737; Downloads: 243
.pdf Fulltext (1,14 MB)
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2.
Household and road dust as indicators of airborne particulate matter elemental composition
Klemen Teran, 2020, doctoral dissertation

Abstract: Household dust (HD) and road dust (RD) are widespread and easily accessible urban sediments, which are influenced by deposition of airborne particulate matter (PM). Since airborne PM is considered to be one of the most important pollutants in urban areas, with significant adverse effects on human health, a better understanding of its elemental composition and dispersion mechanisms is needed. The present study examines whether the HD and RD elemental composition can be used as a quick alternative method for the determination of corresponding PM elemental composition over a selected area. In summer 2016, HD, RD, and topsoil samples were collected from 249 sampling locations distributed across rural, urban, and industrial areas in Slovenia. The collected samples were sieved for particle diameters below 63 μm and analysed for 53 elements with ICP-MS after aqua regia digestion. SEM/EDS analyses were applied for the determination of characteristic particles at the microlevel. Finally, the elemental composition of HD and RD was compared with the PM10 elemental composition obtained from National Network for Ambient Air Quality Monitoring governed by Slovenian Environmental Agency (ARSO) to determine any potential connection between them. The results show that HD and RD are considerably enriched with a large set of elements compared to the topsoil. Correlations and factor analyses show that spatial distribution of factor scores in RD revealed strong regional trends, connected with soil resuspension (Al, Ce, Ga, K, La, Li, P, Rb, Sc and Y) or with anthropogenic sources such as traffic (Ag, Bi, Cu, Sb and Sn), steel mill emissions (Cr, Mo, Mn, Ni and W) and construction material decomposition (Ca and Sr). In contrast, HD elemental composition was highly variable between sampling locations. Variability was probably caused by indoor sources, such as smoking (Ce and La), biomass combustion (K, P and Rb), construction material decomposition (Ca and Sr) and residents’ professional occupation: dental care employees (Ag, Au, Pd) and employees in the metal-processing industry (Cr, Mo, Ni). Among deposited particles in RD, urbanization processes, such as fossil fuel combustion and traffic emissions, including brake pad abrasion and tyre wear, contributed the largest share of particles with anomalous elemental composition. Brake pad abrasion, for instance, contributed Ba-, Cu-, Sn-, and Zn-enriched irregular, angular and tabular particles, while tyre wear produced elongated rubber particles with traces of Ba, Cu, and Zn. RD from urban areas showed significantly higher elemental levels of Ag, Bi, Ca, Cd, Cr, Cu, Hg, Fe, Mo, Nb, Pb, Pt, Sb, Sn, Sr, Ti, Zn, and W in comparison to the rural environment, indicating the strong impact of urbanization on RD elemental composition. Another important anthropogenic source of deposited particles in RD were steel mills. Strong anomalies of Cr, Mo and Ni were detected in their vicinity. Their elemental levels decreased with distancing from the plan location, reaching urban background levels between 15 and 20 km from the mills. SEM/EDS analyses identified enrichments of Cr, Mn, Mo, Ni, V, and W in spherical particles and particles with partially melted surfaces, which were found only in the proximity of steel mills, indicating their influence of the PM deposition. Comparison of RD and the corresponding PM10 elemental composition showed that the RD fraction with particle diameters below 63 μm reflects PM10 elemental composition for the last 30 to 90 days for Cr, Cu, Mo and Zn and can be used as a predictor for PM10 elemental levels. This is not true for HD, as indoor particle sources prevail over the deposition of ambient PM10.
Found in: ključnih besedah
Keywords: household dust, road dust, particulate matter, PM10, pollution, Slovenia, steel mills, topsoil, traffic, urbanization
Published: 02.12.2020; Views: 180; Downloads: 24
.pdf Fulltext (16,34 MB)

3.
Prospects for Indirect Dark Matter Searches with the Cherenkov Telescope Array (CTA)
Gabrijela Zaharijas, John Carr, 2015, published scientific conference contribution

Abstract: The Cherenkov Telescope Array (CTA) will have a unique chance of discovery for a large range of masses in Weakly Interacting Massive Particles models of dark matter. The principal target for dark matter searches with CTA is the centre of the Galactic Halo. The best strategy is to perform CTA observations within a few degrees of the Galactic Centre, with the Galactic Centre itself and the most intense diffuse emission regions removed from the analysis. Assuming a cuspy dark matter density profile for the Milky Way, 500 hours of observations in this region provide sensitivities to and below the thermal cross-section of dark matter annihilations, for masses between a few hundred GeV and a few tens of TeV; therefore CTA will have a significant chance of discovery in some models. Since the dark matter density in the Milky Way is far from certain in the inner kpc region, other targets are also proposed for observation, like ultra-faint dwarf galaxies such as Segue 1 with 100 hours per year proposed. Beyond these two observational targets, further alternatives, such as Galactic dark clumps, will be considered closer to the actual date of CTA operations. Sensitivity predictions for dark matter searches are given on the various targets taking into account the latest instrument response functions expected for CTA together with a discussion on the systematic uncertainties from the backgrounds.
Found in: ključnih besedah
Keywords: dark matter, gamma-ray astronomy
Published: 01.03.2016; Views: 2096; Downloads: 155
.pdf Fulltext (724,07 KB)

4.
Galactic Dark Matter signal and the Fermi-LAT measurement of the diffuse gamma-ray emission
Gabrijela Zaharijas, published scientific conference contribution

Abstract: We study diffuse gamma-ray emission at intermediate Galactic latitudes measured by the Fermi LAT with the aim of searching for a signal from dark matter annihilation or decay. In the absence of a robust dark matter signal, constraints are presented. We present and improve upon conservative dark matter limits obtained with no modeling of the foreground astrophysical diffuse emission. We do so, by taking into account uncertainties in several parameters which characterize conventional astrophysical emission and using a profile likelihood formalism. The resulting limits impact the range of particle masses over which dark matter thermal production in the early Universe is possible, and challenge the interpretation of the PAMELA/Fermi-LAT cosmic ray anomalies as annihilation of dark matter.
Found in: ključnih besedah
Keywords: Dark matter, high-energy gamma rays
Published: 21.03.2016; Views: 2078; Downloads: 0
.pdf Fulltext (1,04 MB)

5.
Optical setup for two-colour experiments at the low density matter beamline of FERMI
Giovanni De Ninno, Paola Finetti, 2017, original scientific article

Found in: ključnih besedah
Keywords: Oprics, low-density matter, free-electron laser
Published: 27.10.2020; Views: 131; Downloads: 0
.pdf Fulltext (1,41 MB)

6.
Asymmetric WIMP Dark Matter in the presence of DM/anti-DM Oscillations
Gabrijela Zaharijas, 2012, published scientific conference contribution abstract

Abstract: The class of ‘Asymmetric Dark Matter’ scenarios relies on the existence of a primordial particle/anti-particle asymmetry in the dark sector related to the baryon asymmetry as a way to address the observed similarity between the baryonic and dark matter energy densities today. Focusing on this framework we calculate the evolution of the dark matter relic abundance in the presence of particle/anti-particle oscillations. We show how oscillations reopen the parameter space of asymmetric dark matter models, in particular in the direction of allowing large (WIMP-scale) DM masses. Finally, we constrain the parameter space in this framework by applying up-to-date bounds from indirect detection signals on annihilating DM.
Found in: ključnih besedah
Keywords: dark matter, early universe
Published: 23.03.2016; Views: 1799; Downloads: 0
.pdf Fulltext (431,48 KB)

7.
Search for Spectral Irregularities due to Photon-Axionlike-Particle Oscillations With the Fermi Large Area Telescope
Gabrijela Zaharijas, 2016, original scientific article

Found in: ključnih besedah
Summary of found: ...dark matter, gammarays theory, gamma rays experiment...
Keywords: dark matter, gammarays theory, gamma rays experiment
Published: 26.04.2016; Views: 2381; Downloads: 0
.pdf Fulltext (801,77 KB)

8.
Constraints on the Galactic Dark Matter signal from the Fermi-LAT measurement of the diffuse gamma-ray emission
Gabrijela Zaharijas, 2012, published scientific conference contribution

Abstract: We study diffuse gamma-ray emission at intermediate Galactic latitudes measured by the Fermi Large Area Telescope with the aim of searching for a signal from dark matter annihilation or decay. In the absence of a robust dark matter signal, constraints are presented. We set both, conservative dark matter limits requiring that the dark matter signal does not exceed the observed diffuse gamma-ray emission and limits derived based on modeling the foreground astrophysical diffuse emission. Uncertainties in several parameters which characterize conventional astrophysical emission are taken into account using a profile likelihood formalism. The resulting limits impact the range of particle masses over which dark matter thermal production in the early Universe is possible, and challenge the interpretation of the PAMELA/Fermi-LAT cosmic ray anomalies as annihilation of dark matter.
Found in: ključnih besedah
Keywords: gamma rays, Galactic diffuse emission, dark matter serach
Published: 03.05.2016; Views: 1806; Downloads: 0
.pdf Fulltext (1,42 MB)

9.
10.
Extragalactic gamma-ray signal from dark matter annihilation
Gabrijela Zaharijas, E. Sefusatti, Pasquale D. Serpico, D. Theurel, M. Gustafsson, 2014, original scientific article

Found in: ključnih besedah
Keywords: cosmology, dark matter, diffuse background, gamma-rays
Published: 09.05.2017; Views: 1587; Downloads: 67
URL Fulltext (0,00 KB)

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