SwePub
Sök i SwePub databas

  Utökad sökning

Träfflista för sökning "LAR1:nrm ;hsvcat:2"

Sökning: LAR1:nrm > Teknik

  • Resultat 1-7 av 7
Sortera/gruppera träfflistan
   
NumreringReferensOmslagsbildHitta
1.
  • Billström, Kjell, et al. (författare)
  • Sandstone-hosted Pb-Zn deposits along the margin of the Scandinavian Caledonides and their possible relationship with nearby Pb-Zn vein mineralisation
  • 2020
  • Ingår i: Ore Geology Reviews. - : Elsevier BV. - 0169-1368 .- 1872-7360. ; 127
  • Forskningsöversikt (refereegranskat)abstract
    • Numerous sandstone-hosted Pb-Zn deposits occur along the present-day erosional front of the eastern Scandinavian Caledonides. The largest deposit is Laisvall (64.3 Mt at 4.0% Pb, 0.6% Zn and 9.0 g/t Ag) and since mineralisations generally share similar characteristics (reminding of both SEDEX and MVT-style) the term Laisvall-type has often been used. Typically, mineralised zones occur along sedimentary bedding and consist of disseminated galena and sphalerite and lesser amounts of calcite, fluorite, baryte, pyrite and sericite forming a cement that fill interstitial pores in Neoproterozoic/Eocambrian (e.g. Laisvall) to Cambrian (e.g. Vassbo) sandstones. Deposits occur both in autochtonous and allochtonous sedimentary rocks, and a broad consensus exists about their epigenetic nature, their spatial relationships to syn-sedimentary faults and that ore fluids have scavenged metals from the crystalline basement. However, the detailed ore depositional history and the timing of ore deposition have remained more controversial. New analyses aimed to complement earlier Rb-Sr data (crush-leach technique using sphalerite) fail to support a published three-point isochron age of 467 +/- 5 Ma. This is probably due to syn-ore mixing between fluids carrying isotopically variable strontium and inherited problems to analyse sphalerite grains that strictly were deposited from a single ore pulse. Tentatively, strontium in the ores originate from a mix of components derived from the basement, seawater and the local sedimentary host sequences. The lead component has highly radiogenic compositions, and data define sub-parallel linear arrays interpreted to essentially represent mixing of isotopically different types of lead released from regional basement rocks. There are obvious similarities when comparing features of deposits representing two Pb-Zn ore styles, the sandstone-hosted dissemination and the fracture-controlled mineralisation in the granite-dominated basement occurring further east of the Caledonian margin. These include low temperature brines responsible for mineral deposition, the mineralogy and the nature of Rb-Sr and Pb isotope data. We suggest that these types of mineralisation have a common origin and time of emplacement, but it is elusive to propose a well-constrained age. Nonetheless, field observations and other evidence suggest that ore formation is due to large-scale fluid flow triggered by the transition from an extensional to compressional tectonic setting at about 500 Ma. Connected to this mid-Cambrian stage was the development of syn-sedimentary faults and fractures in the basement and in overlying consolidated sandstones. The opening of such zones of weakness enabled a movement of ore-forming fluids infilling pore space in sandstones (disseminated ore) and fractures in the basement (vein ore).
  •  
2.
  • Dussex, Nicolas, et al. (författare)
  • Moose genomes reveal past glacial demography and the origin of modern lineages
  • 2020
  • Ingår i: BMC Genomics. - : Springer Science and Business Media LLC. - 1471-2164. ; 21:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Numerous megafauna species from northern latitudes went extinct during the Pleistocene/Holocene transition as a result of climate-induced habitat changes. However, several ungulate species managed to successfully track their habitats during this period to eventually flourish and recolonise the holarctic regions. So far, the genomic impacts of these climate fluctuations on ungulates from high latitudes have been little explored. Here, we assemble a de-novo genome for the European moose (Alces alces) and analyse it together with re-sequenced nuclear genomes and ancient and modern mitogenomes from across the moose range in Eurasia and North America.Results: We found that moose demographic history was greatly influenced by glacial cycles, with demographic responses to the Pleistocene/Holocene transition similar to other temperate ungulates. Our results further support that modern moose lineages trace their origin back to populations that inhabited distinct glacial refugia during the Last Glacial Maximum (LGM). Finally, we found that present day moose in Europe and North America show low to moderate inbreeding levels resulting from post-glacial bottlenecks and founder effects, but no evidence for recent inbreeding resulting from human-induced population declines.Conclusions: Taken together, our results highlight the dynamic recent evolutionary history of the moose and provide an important resource for further genomic studies.
  •  
3.
  • Faxneld, Suzanne, et al. (författare)
  • Temporal Trends and Geographical Differences of Perfluoroalkyl Acids in Baltic Sea Herring and White-Tailed Sea Eagle Eggs in Sweden
  • 2016
  • Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 50:23, s. 13070-13079
  • Tidskriftsartikel (refereegranskat)abstract
    • Temporal and spatial trends of perfluoroalkyl acids (PFAAs) were investigated in Baltic Sea herring liver (Clupea harengus) from three sites, and white-tailed sea eagle (WTSE) eggs (Haliaeetus albicilla) from two freshwater and two marine areas in Sweden. Trends of most quantifiable PFAAs increased over the monitored period (1980-2014 in herring, 1960s/1980s-2010 in WTSE). No significant decreasing trends were observed for the most recent ten years for any substances, except perfluorooctane sulfonamide (FOSA). Concentrations of perfluorooctanesulfonic acids (PFOS) in herring showed a distinct decreasing spatial trend moving from the more southern site toward the more northern site, indicating main input of PFOS into the southern Baltic Sea. For WTSE, PFOS concentration was higher in the marine compared to the freshwater environment, explained by the cumulative historic contamination of the Baltic Sea. Similarly, concentrations in WTSE were lower in the northern part of the Baltic Sea compared to further south. Concentrations of PFUnDA, representing long-chain perfluoroalkyl carboxylic acids (PFCAs), showed a more homogeneous spatial distribution compared to PFOS for both herring and WTSE, indicating that atmospheric inputs (via precursors) of the long-chain PFCAs are important contributors in the study areas.
  •  
4.
  • Gebbink, Wouter A., et al. (författare)
  • Perfluoroalkyl Acids (PFAAs) and Selected Precursors in the Baltic Sea Environment : Do Precursors Play a Role in Food Web Accumulation of PFAAs?
  • 2016
  • Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 50:12, s. 6354-6362
  • Tidskriftsartikel (refereegranskat)abstract
    • The present study examined the presence of perfluoroalkyl acids (PFAAs) and selected precursors in the Baltic Sea abiotic environment and guillemot food web, and investigated the relative importance of precursors in food web accumulation of PFAAs. Sediment, water, zooplankton, herring, sprat, and guillemot eggs were analyzed for perfluoroalkane sulfonic acids (PFSAs; C-4,C-6,C-8,C-10) and perfluoroalkyl carboxylic acids (PFCAs; C6-15) along with six perfluorooctane sulfonic acid (PFOS) precursors and 11 polyfluoroalkyl phosphoric acid diesters (diPAPs). FOSA, FOSAA. and its methyl and ethyl derivatives (Me- and EtFOSAA), and 6:2/6:2 diPAP were detected in sediment and water. While FOSA and the three FOSAAs were detected in all biota, a total of nine diPAPs were only detected in zooplankton. Concentrations of PFOS precursors and diPAPs exceeded PFOS and PFCA concentrations, respectively, in zooplankton, but not in fish and guillemot eggs. Although PFOS precursors were present at all trophic levels, they appear to play a minor role in food web accumulation of PFOS based on PFOS precursor/PFOS ratios and PFOS and FOSA isomer patterns. The PFCA pattern in fish could not be explained by the intake pattern based on PFCAs and analyzed precursors, that is, diPAPs. Exposure to additional precursors might therefore be a dominant exposure pathway compared to direct PFCA exposure for fish.
  •  
5.
  • Pujolar, J. M., et al. (författare)
  • First de novo whole genome sequencing and assembly of the pink-footed goose
  • 2018
  • Ingår i: Genomics. - : Elsevier BV. - 0888-7543 .- 1089-8646. ; 110:2, s. 75-79
  • Tidskriftsartikel (refereegranskat)abstract
    • Annotated genomes can provide new perspectives on the biology of species. We present the first de novo whole genome sequencing for the pink-footed goose. In order to obtain a high-quality de novo assembly the strategy used was to combine one short insert paired-end library with two mate-pair libraries. The pink-footed goose genome was assembled de novo using three different assemblers and an assembly evaluation was subsequently performed in order to choose the best assembler. For our data, ALLPATHS-LG performed the best, since the assembly produced covers most of the genome, while introducing the fewest errors. A total of 26,134 genes were annotated, with bird species accounting for virtually all BLAST hits. We also estimated the substitution rate in the pink-footed goose, which can be of use in future demographic studies, by using a comparative approach with the genome of the chicken, the mallard and the swan goose. A substitution rate of 1.38 x 10(-7) per nucleotide per generation was obtained when comparing the genomes of the two closely-related goose species (the pink-footed and the swan goose). Altogether, we provide a valuable tool for future genomic studies aiming at particular genes and regions of the pink-footed goose genome as well as other bird species.
  •  
6.
  •  
7.
  • De Colle, Mattia, et al. (författare)
  • Study of the Dissolution of Stainless-Steel Slag Minerals in Different Acid Environments to Promote Their Use for the Treatment of Acidic Wastewaters
  • 2021
  • Ingår i: Applied Sciences. - : MDPI AG. - 2076-3417. ; 11:24
  • Tidskriftsartikel (refereegranskat)abstract
    • Several stainless-steel slags have been successfully employed in previous studies as substitutes for lime in the treatment of industrial acidic wastewaters. This study deepens the knowledge of such application, by analyzing the neutralizing capacity of different slags related to their mineral compositions. To do so, firstly the chemical and mineral compositions of all the slag samples are assessed. Then, 0.5 g, 1 g, 2 g of each slag and 0.25 g and 0.5 g of lime are used to neutralize 100 g of 0.1 M HCl or HNO3 solutions. After the has neutralization occurred, the solid residues are extracted and analyzed using XRD spectroscopy. Then, the solubility of the minerals is assessed and ranked, by comparing the XRD spectra of the residues with the obtained pH values. The results show that minerals such as dicalcium silicate and bredigite are highly soluble in the selected experimental conditions, while minerals such as merwinite and akermanite, only partially. Moreover, Al-rich slags seem to perform poorly due to the formation of hydroxides, which generate extra protons. However, when the weight of slag is adequately adjusted, Al-rich slags can increase the pH values to higher levels compared to the other studied slags.
  •  
Skapa referenser, mejla, bekava och länka
  • Resultat 1-7 av 7

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.

 
pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy