| 1. |
- Crippa, M., et al.
(author)
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Organic aerosol components derived from 25 AMS data sets across Europe using a consistent ME-2 based source apportionment approach
- 2014
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In: Atmospheric Chemistry and Physics. - : Copernicus GmbH. - 1680-7324. ; 14:12, s. 6159-6176
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Journal article (peer-reviewed)abstract
- Organic aerosols (OA) represent one of the major constituents of submicron particulate matter (PM1) and comprise a huge variety of compounds emitted by different sources. Three intensive measurement field campaigns to investigate the aerosol chemical composition all over Europe were carried out within the framework of the European Integrated Project on Aerosol Cloud Climate and Air Quality Interactions (EUCAARI) and the intensive campaigns of European Monitoring and Evaluation Programme (EMEP) during 2008 (May-June and September-October) and 2009 (February-March). In this paper we focus on the identification of the main organic aerosol sources and we define a standardized methodology to perform source apportionment using positive matrix factorization (PMF) with the multilinear engine (ME-2) on Aerodyne aerosol mass spectrometer (AMS) data. Our source apportionment procedure is tested and applied on 25 data sets accounting for two urban, several rural and remote and two high altitude sites; therefore it is likely suitable for the treatment of AMS-related ambient data sets. For most of the sites, four organic components are retrieved, improving significantly previous source apportionment results where only a separation in primary and secondary OA sources was possible. Generally, our solutions include two primary OA sources, i.e. hydrocarbon-like OA (HOA) and biomass burning OA (BBOA) and two secondary OA components, i.e. semi-volatile oxygenated OA (SV-OOA) and low-volatility oxygenated OA (LV-OOA). For specific sites cooking-related (COA) and marine-related sources (MSA) are also separated. Finally, our work provides a large overview of organic aerosol sources in Europe and an interesting set of highly time resolved data for modeling purposes.
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| 2. |
- Genberg, Johan, et al.
(author)
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Light-absorbing carbon in Europe - measurement and modelling, with a focus on residential wood combustion emissions
- 2013
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In: Atmospheric Chemistry And Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 13:17, s. 8719-8738
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Journal article (peer-reviewed)abstract
- The atmospheric concentration of elemental carbon (EC) in Europe during the six-year period 2005-2010 has been simulated with the EMEP MSC-W model. The model bias compared to EC measurements was less than 20% for most of the examined sites. The model results suggest that fossil fuel combustion is the dominant source of EC in most of Europe but that there are important contributions also from residential wood burning during the cold seasons and, during certain episodes, also from open biomass burning (wildfires and agricultural fires). The modelled contributions from open biomass fires to ground level concentrations of EC were small at the sites included in the present study, <3% of the long-term average of EC in PM10. The modelling of this EC source is subject to many uncertainties, and it was likely underestimated for some episodes. EC measurements and modelled EC were also compared to optical measurements of black carbon (BC). The relationships between EC and BC (as given by mass absorption cross section, MAC, values) differed widely between the sites, and the correlation between observed EC and BC is sometimes poor, making it difficult to compare results using the two techniques and limiting the comparability of BC measurements to model EC results. A new bottom-up emission inventory for carbonaceous aerosol from residential wood combustion has been applied. For some countries the new inventory has substantially different EC emissions compared to earlier estimates. For northern Europe the most significant changes are much lower emissions in Norway and higher emissions in neighbouring Sweden and Finland. For Norway and Sweden, comparisons to source-apportionment data from winter campaigns indicate that the new inventory may improve model-calculated EC from wood burning. Finally, three different model setups were tested with variable atmospheric lifetimes of EC in order to evaluate the model sensitivity to the assumptions regarding hygroscopicity and atmospheric ageing of EC. The standard ageing scheme leads to a rapid transformation of the emitted hydrophobic EC to hygroscopic particles, and generates similar results when assuming that all EC is aged at the point of emission. Assuming hydrophobic emissions and no ageing leads to higher EC concentrations. For the more remote sites, the observed EC concentration was in between the modelled EC using standard ageing and the scenario treating EC as hydrophobic. This could indicate too-rapid EC ageing in the model in relatively clean parts of the atmosphere.
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| 3. |
- Bargi, Sara, et al.
(author)
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Vortices in rotating two-component boson and fermion traps
- 2010
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In: Physica E-Low-Dimensional Systems & Nanostructures. - : Elsevier BV. - 1386-9477. ; 42:3, s. 411-415
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Conference paper (peer-reviewed)abstract
- Quantum liquids may carry angular momentum by the formation of vortex states. This is well known for Bose-Einstein condensates in rotating traps, and was even found to occur in quantum dots at strong magnetic fields. Here we consider a two-component quantum liquid, where coreless vortices and interlaced lattices of coreless vortices appear in a very similar way for fermions and bosons with repulsive two-body interactions. The ground states at given angular momentum, as well as the pair correlations for equal and different numbers of atoms in the two components, are studied. (C) 2009 Elsevier B.V. All rights reserved.
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| 4. |
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| 5. |
- Lindroth, Anders M., et al.
(author)
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Two S-adenosylmethionine synthetase-encoding genes that are differentially expressed during adventitious root development in Pinus Contorta
- 2001
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In: Plant Molecular Biology. - 0167-4412 .- 1573-5028. ; 46:3, s. 335-346
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Journal article (peer-reviewed)abstract
- Two S-adenosylmethionine synthetase (SAMS) cDNAs, PcSAMS1 and PcSAMS2, have been identified in Pinus contorta. We found that the two genes are differentially expressed during root development. Thus, PcSAMS1 is preferentially expressed in roots and exhibits a specific expression pattern in the meristem at the onset of adventitious root development, whereas PcSAMS2 is expressed in roots as well as in shoots and is down-regulated during adventitious root formation. The expression of the two SAMS genes is different from the SAMS activity levels during adventitious root formation. We conclude that other SAMS genes that remain to be characterized may contribute to the observed SAMS activity, or that the activities of PcSAMS1 and PcSAMS2 are affected by post-transcriptional regulation. The deduced amino acid sequences of PcSAMS1 and PcSAMS2 are highly divergent, suggesting different functional roles. However, both carry the two perfectly conserved motifs that are common to all plant SAMS. At the protein level, PcSAMS2 shares about 90% identity to other isolated eukaryotic SAMS, while PcSAMS1 shares less than 50% identity with other plant SAMS. In a phylogenetic comparison, PcSAMS1 seems to have diverged significantly from all other SAMS genes. Nevertheless, PcSAMS1 was able to complement a Saccharomyces cerevisiae sam1 sam2 double mutant, indicating that it encodes a functional SAMS enzyme.
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| 6. |
- Martikainen, Maria-Viola, et al.
(author)
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TUBE project: Transport-derived ultrafines and the brain effects
- 2022
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In: International Journal of Environmental Research and Public Health. - : MDPI. - 1661-7827 .- 1660-4601. ; 19:1
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Journal article (peer-reviewed)abstract
- The adverse effects of air pollutants on the respiratory and cardiovascular systems are unquestionable. However, in recent years, indications of effects beyond these organ systems have become more evident. Traffic-related air pollution has been linked with neurological diseases, exacerbated cognitive dysfunction, and Alzheimer’s disease. However, the exact air pollutant compositions and exposure scenarios leading to these adverse health effects are not known. Although several components of air pollution may be at play, recent experimental studies point to a key role of ultrafine particles (UFPs). While the importance of UFPs has been recognized, almost nothing is known about the smallest fraction of UFPs, and only >23 nm emissions are regulated in the EU. Moreover, the role of the semivolatile fraction of the emissions has been neglected. The Transport-Derived Ultrafines and the Brain Effects (TUBE) project will increase knowledge on harmful ultrafine air pollutants, as well as semivolatile compounds related to adverse health effects. By including all the major current combustion and emission control technologies, the TUBE project aims to provide new information on the adverse health effects of current traffic, as well as information for decision makers to develop more effective emission legislation. Most importantly, the TUBE project will include adverse health effects beyond the respiratory system; TUBE will assess how air pollution affects the brain and how air pollution particles might be removed from the brain. The purpose of this report is to describe the TUBE project, its background, and its goals.
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| 7. |
- Paglione, M., et al.
(author)
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Primary and secondary biomass burning aerosols determined by proton nuclear magnetic resonance (H-1-NMR) spectroscopy during the 2008 EUCAARI campaign in the Po Valley (Italy)
- 2014
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In: Atmospheric Chemistry and Physics. - : Copernicus GmbH. - 1680-7324. ; 14:10, s. 5089-5110
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Journal article (peer-reviewed)abstract
- Atmospheric organic aerosols are generally classified as primary and secondary (POA and SOA) according to their formation processes. An actual separation, however, is challenging when the timescales of emission and gas-to-particle formation overlap. The presence of SOA formation in biomass burning plumes leads to scientific questions about whether the oxidized fraction of biomass burning aerosol is rather of secondary or primary origin, as some studies would suggest, and about the chemical compositions of oxidized biomass burning POA and SOA. In this study, we apply nuclear magnetic resonance (NMR) spectroscopy to investigate the functional group composition of fresh and aged biomass burning aerosols during an intensive field campaign in the Po Valley, Italy. The campaign was part of the EUCAARI project and was held at the rural station of San Pietro Capofiume in spring 2008. Factor analysis applied to the set of NMR spectra was used to apportion the wood burning contribution and other organic carbon (OC) source contributions, including aliphatic amines. Our NMR results, referred to the polar, water-soluble fraction of OC, show that fresh wood burning particles are composed of polyols and aromatic compounds, with a sharp resemblance to wood burning POA produced in wood stoves, while aged samples are clearly depleted of alcohols and are enriched in aliphatic acids with a smaller contribution of aromatic compounds. The comparison with biomass burning organic aerosols (BBOA) determined by high-resolution aerosol mass spectrometry (HR-TOF-AMS) at the site shows only a partial overlap between NMR BB-POA and AMS BBOA, which can be explained by either the inability of BBOA to capture all BB-POA composition, especially the alcohol fraction, or the fact that BBOA account for insoluble organic compounds unmeasured by the NMR. Therefore, an unambiguous composition for biomass burning POA could not be derived from this study, with NMR analysis indicating a higher O / C ratio compared to that measured for AMS BBOA. The comparison between the two techniques substantially improves when adding factors tracing possible contributions from biomass burning SOA, showing that the operational definitions of biomass burning organic aerosols are more consistent between techniques when including more factors tracing chemical classes over a range of oxidation levels. Overall, the non-fossil total carbon fraction was 50-57%, depending on the assumptions about the C-14 content of non-fossil carbon, and the fraction of organic carbon estimated to be oxidized organic aerosol (OOA) from HR-TOF-AMS measurements was 73-100% modern.
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| 8. |
- Pascual, Unai, et al.
(author)
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Valuing nature's contributions to people : the IPBES approach
- 2017
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In: Current Opinion in Environmental Sustainability. - : Elsevier BV. - 1877-3435. ; 26-27, s. 7-16
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Research review (peer-reviewed)abstract
- Nature is perceived and valued in starkly different and often conflicting ways. This paper presents the rationale for the inclusive valuation of nature's contributions to people (NCP) in decision making, as well as broad methodological steps for doing so. While developed within the context of the Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES), this approach is more widely applicable to initiatives at the knowledge–policy interface, which require a pluralistic approach to recognizing the diversity of values. We argue that transformative practices aiming at sustainable futures would benefit from embracing such diversity, which require recognizing and addressing power relationships across stakeholder groups that hold different values on human nature-relations and NCP.
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| 9. |
- Saarikoski, H., et al.
(author)
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Coreless vortices in rotating two-component quantum droplets
- 2010
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In: Europhysics Letters. - : IOP Publishing. - 0295-5075. ; 91:3
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Journal article (peer-reviewed)abstract
- The rotation of a quantum liquid induces vortices to carry angular momentum. When the system is composed of multiple components that are distinguishable from each other, vortex cores in one component may be filled by particles of the other component, and coreless vortices form. Based on evidence from computational methods, here we show that the formation of coreless vortices occurs very similarly for repulsively interacting bosons and fermions, largely independent of the form of the particle interactions. We further address the connection to the Halperin wave functions of non-polarized quantum Hall states. Copyright (c) EPLA, 2010
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| 10. |
- Saarikoski, H, et al.
(author)
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Stability of vortex structures in quantum dots
- 2005
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In: Physical Review B (Condensed Matter and Materials Physics). - 1098-0121. ; 71:3
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Journal article (peer-reviewed)abstract
- We study the stability and structure of vortices emerging in two-dimensional quantum dots in high magnetic fields. Our results obtained with exact diagonalization and density-functional calculations show that vortex structures can be found in various confining potentials. In nonsymmetric external potentials we find off-electron vortices that are localized giving rise to charge deficiency or holes in the electron density with rotating currents around them. We discuss the role of quantum fluctuations and show that vortex formation is observable in the energetics of the system. Our findings suggest that vortices can be used to characterize the solutions in high magnetic fields, giving insight into the underlying internal structure of the electronic wave function.
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