| 1. |
- Andersson, Per A., et al.
(författare)
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Anger and disgust shape judgments of social sanctions across cultures, especially in high individual autonomy societies
- 2024
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Ingår i: Scientific Reports. - : Nature Research. - 2045-2322. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- When someone violates a social norm, others may think that some sanction would be appropriate. We examine how the experience of emotions like anger and disgust relate to the judged appropriateness of sanctions, in a pre-registered analysis of data from a large-scale study in 56 societies. Across the world, we find that individuals who experience anger and disgust over a norm violation are more likely to endorse confrontation, ostracism and, to a smaller extent, gossip. Moreover, we find that the experience of anger is consistently the strongest predictor of judgments of confrontation, compared to other emotions. Although the link between state-based emotions and judgments may seem universal, its strength varies across countries. Aligned with theoretical predictions, this link is stronger in societies, and among individuals, that place higher value on individual autonomy. Thus, autonomy values may increase the role that emotions play in guiding judgments of social sanctions.
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| 2. |
- van Dishoeck, E. F., et al.
(författare)
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Water in star-forming regions: Physics and chemistry from clouds to disks as probed by Herschel spectroscopy
- 2021
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 648
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Tidskriftsartikel (refereegranskat)abstract
- Context. Water is a key molecule in the physics and chemistry of star and planet formation, but it is difficult to observe from Earth. The Herschel Space Observatory provided unprecedented sensitivity as well as spatial and spectral resolution to study water. The Water In Star-forming regions with Herschel (WISH) key program was designed to observe water in a wide range of environments and provide a legacy data set to address its physics and chemistry. Aims. The aim of WISH is to determine which physical components are traced by the gas-phase water lines observed with Herschel and to quantify the excitation conditions and water abundances in each of these components. This then provides insight into how and where the bulk of the water is formed in space and how it is transported from clouds to disks, and ultimately comets and planets. Methods. Data and results from WISH are summarized together with those from related open time programs. WISH targeted ∼80 sources along the two axes of luminosity and evolutionary stage: from low- to high-mass protostars (luminosities from <1 to > 10Lpdbl) and from pre-stellar cores to protoplanetary disks. Lines of H2O and its isotopologs, HDO, OH, CO, and [O I], were observed with the HIFI and PACS instruments, complemented by other chemically-related molecules that are probes of ultraviolet, X-ray, or grain chemistry. The analysis consists of coupling the physical structure of the sources with simple chemical networks and using non-LTE radiative transfer calculations to directly compare models and observations. Results. Most of the far-infrared water emission observed with Herschel in star-forming regions originates from warm outflowing and shocked gas at a high density and temperature (> 10cm-3, 300-1000 K, v ∼ 25 km s-1), heated by kinetic energy dissipation. This gas is not probed by single-dish low-J CO lines, but only by CO lines with Jup > 14. The emission is compact, with at least two different types of velocity components seen. Water is a significant, but not dominant, coolant of warm gas in the earliest protostellar stages. The warm gas water abundance is universally low: orders of magnitude below the H2O/H2 abundance of 4 × 10-4 expected if all volatile oxygen is locked in water. In cold pre-stellar cores and outer protostellar envelopes, the water abundance structure is uniquely probed on scales much smaller than the beam through velocity-resolved line profiles. The inferred gaseous water abundance decreases with depth into the cloud with an enhanced layer at the edge due to photodesorption of water ice. All of these conclusions hold irrespective of protostellar luminosity. For low-mass protostars, a constant gaseous HDO/H2O ratio of ∼0.025 with position into the cold envelope is found. This value is representative of the outermost photodesorbed ice layers and cold gas-phase chemistry, and much higher than that of bulk ice. In contrast, the gas-phase NH3 abundance stays constant as a function of position in low-mass pre- and protostellar cores. Water abundances in the inner hot cores are high, but with variations from 5 × 10-6 to a few × 10-4 for low- and high-mass sources. Water vapor emission from both young and mature disks is weak. Conclusions. The main chemical pathways of water at each of the star-formation stages have been identified and quantified. Low warm water abundances can be explained with shock models that include UV radiation to dissociate water and modify the shock structure. UV fields up to 102-10times the general interstellar radiation field are inferred in the outflow cavity walls on scales of the Herschel beam from various hydrides. Both high temperature chemistry and ice sputtering contribute to the gaseous water abundance at low velocities, with only gas-phase (re-)formation producing water at high velocities. Combined analyses of water gas and ice show that up to 50% of the oxygen budget may be missing. In cold clouds, an elegant solution is that this apparently missing oxygen is locked up in larger μm-sized grains that do not contribute to infrared ice absorption. The fact that even warm outflows and hot cores do not show H2O at full oxygen abundance points to an unidentified refractory component, which is also found in diffuse clouds. The weak water vapor emission from disks indicates that water ice is locked up in larger pebbles early on in the embedded Class I stage and that these pebbles have settled and drifted inward by the Class II stage. Water is transported from clouds to disks mostly as ice, with no evidence for strong accretion shocks. Even at abundances that are somewhat lower than expected, many oceans of water are likely present in planet-forming regions. Based on the lessons for galactic protostars, the low-J H2O line emission (Eup < 300 K) observed in extragalactic sources is inferred to be predominantly collisionally excited and to originate mostly from compact regions of current star formation activity. Recommendations for future mid- to far-infrared missions are made.
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| 3. |
- Allentoft, Morten E., et al.
(författare)
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Population genomics of post-glacial western Eurasia
- 2024
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Ingår i: Nature. - 0028-0836 .- 1476-4687. ; 625:7994, s. 301-311
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Tidskriftsartikel (refereegranskat)abstract
- Western Eurasia witnessed several large-scale human migrations during the Holocene1–5. Here, to investigate the cross-continental effects of these migrations, we shotgun-sequenced 317 genomes—mainly from the Mesolithic and Neolithic periods—from across northern and western Eurasia. These were imputed alongside published data to obtain diploid genotypes from more than 1,600 ancient humans. Our analyses revealed a ‘great divide’ genomic boundary extending from the Black Sea to the Baltic. Mesolithic hunter-gatherers were highly genetically differentiated east and west of this zone, and the effect of the neolithization was equally disparate. Large-scale ancestry shifts occurred in the west as farming was introduced, including near-total replacement of hunter-gatherers in many areas, whereas no substantial ancestry shifts happened east of the zone during the same period. Similarly, relatedness decreased in the west from the Neolithic transition onwards, whereas, east of the Urals, relatedness remained high until around 4,000 bp, consistent with the persistence of localized groups of hunter-gatherers. The boundary dissolved when Yamnaya-related ancestry spread across western Eurasia around 5,000 bp, resulting in a second major turnover that reached most parts of Europe within a 1,000-year span. The genetic origin and fate of the Yamnaya have remained elusive, but we show that hunter-gatherers from the Middle Don region contributed ancestry to them. Yamnaya groups later admixed with individuals associated with the Globular Amphora culture before expanding into Europe. Similar turnovers occurred in western Siberia, where we report new genomic data from a ‘Neolithic steppe’ cline spanning the Siberian forest steppe to Lake Baikal. These prehistoric migrations had profound and lasting effects on the genetic diversity of Eurasian populations.
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| 4. |
- Bouhafs, Chamseddine, et al.
(författare)
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Structural properties and dielectric function of graphene grown by high-temperature sublimation on 4H-SiC(000-1)
- 2015
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Ingår i: Journal of Applied Physics. - : American Institute of Physics (AIP). - 0021-8979 .- 1089-7550. ; 117:8, s. 085701-
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Tidskriftsartikel (refereegranskat)abstract
- Understanding and controlling growth of graphene on the carbon face (C-face) of SiC presents a significant challenge. In this work, we study the structural, vibrational, and dielectric function properties of graphene grown on the C-face of 4H-SiC by high-temperature sublimation in an argon atmosphere. The effect of growth temperature on the graphene number of layers and crystallite size is investigated and discussed in relation to graphene coverage and thickness homogeneity. An amorphous carbon layer at the interface between SiC and the graphene is identified, and its evolution with growth temperature is established. Atomic force microscopy, micro-Raman scattering spectroscopy, spectroscopic ellipsometry, and high-resolution cross-sectional transmission electron microscopy are combined to determine and correlate thickness, stacking order, dielectric function, and interface properties of graphene. The role of surface defects and growth temperature on the graphene growth mechanism and stacking is discussed, and a conclusion about the critical factors to achieve decoupled graphene layers is drawn. (C) 2015 AIP Publishing LLC.
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| 5. |
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| 6. |
- Dahlqvist, Martin, et al.
(författare)
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Complex magnetism in nanolaminated Mn2GaC
- 2014
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- We have used first-principles calculations and Heisenberg Monte Carlo simulations to search for the magnetic ground state of Mn2GaC, a recently synthesized magnetic nanolaminate. We have, independent on method, identified a range of low energy collinear as well as non-collinear magnetic configurations, indicating a highly frustrated magnetic material with several nearly degenerate magnetic states. An experimentally obtained magnetization of only 0.29 per Mn atom in Mn2GaC may be explained by canted spins in an antiferromagnetic configuration of ferromagnetically ordered sub-layers with alternating spin orientation, denoted AFM[0001]. Furthermore, low temperature X-ray diffraction show a new basal plane peak appearing upon a magnetic transition, which is consistent with the here predicted change in inter-layer spacing for the AFM[0001] configuration.
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| 7. |
- Ekström, Erik, et al.
(författare)
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The effects of microstructure, Nb content and secondary Ruddlesden-Popper phase on thermoelectric properties in perovskite CaMn1-xNbxO3 (x=0-0.10) thin films
- 2020
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Ingår i: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 10:13, s. 7918-7926
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Tidskriftsartikel (refereegranskat)abstract
- CaMn1-xNbxO3 (x = 0, 0.5, 0.6, 0.7 and 0.10) thin films have been grown by a two-step sputtering/annealing method. First, rock-salt-structured (Ca,Mn1-x,Nb-x)O thin films were deposited on 11 & x304;00 sapphire using reactive RF magnetron co-sputtering from elemental targets of Ca, Mn and Nb. The CaMn1-xNbxO3 films were then obtained by thermally induced phase transformation from rock-salt-structured (Ca,Mn1-xNbx)O to orthorhombic during post-deposition annealing at 700 degrees C for 3 h in oxygen flow. The X-ray diffraction patterns of pure CaMnO3 showed mixed orientation, while Nb-containing films were epitaxially grown in [101] out of-plane-direction. Scanning transmission electron microscopy showed a Ruddlesden-Popper (R-P) secondary phase in the films, which results in reduction of the electrical and thermal conductivity of CaMn1-xNbxO3. The electrical resistivity and Seebeck coefficient of the pure CaMnO3 film were measured to 2.7 omega cm and -270 mu V K-1 at room temperature, respectively. The electrical resistivity and Seebeck coefficient were reduced by alloying with Nb and was measured to 0.09 omega cm and -145 mu V K-1 for x = 0.05. Yielding a power factor of 21.5 mu W K-2 m(-1) near room temperature, nearly eight times higher than for pure CaMnO3 (2.8 mu W K-2 m(-1)). The power factors for alloyed samples are low compared to other studies on phase-pure material. This is due to high electrical resistivity originating from the secondary R-P phase. The thermal conductivity of the CaMn1-xNbxO3 films is low for all samples and is the lowest for x = 0.07 and 0.10, determined to 1.6 W m(-1) K-1. The low thermal conductivity is attributed to grain boundary scattering and the secondary R-P phase.
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| 8. |
- Halim, Joseph, et al.
(författare)
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Electronic and optical characterization of 2D Ti2C and Nb2C (MXene) thin films
- 2019
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Ingår i: Journal of Physics. - : IOP PUBLISHING LTD. - 0953-8984 .- 1361-648X. ; 31:16
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Tidskriftsartikel (refereegranskat)abstract
- Two-dimensional (2D) transition metal carbides and/or nitrides (MXenes) are a new class of 2D materials, with extensive opportunities for property tailoring due to the numerous possibilities for varying chemistries and surface terminations. Here, Ti2AlC and Nb2AlC MAX phase epitaxial thin films were deposited on sapphire substrates by physical vapor deposition. The films were then etched in LiF/HCl solutions, yielding Li-intercalated, 2D Ti2CTz and Nb2CTz films, whose terminations, transport and optical properties were characterized. The former exhibits metallic conductivity, with weak localization below 50 K. In contrast, the Nb-based film exhibits an increase in resistivity with decreasing temperature from RT down to 40K consistent with variable range hopping transport. The optical properties of both films were determined from spectroscopic ellipsometry in the 0.75 to 3.50 eV range. The results for Ti2Clz films confirm the metallic behavior. In contrast, no evidence of metallic behavior is observed for the Nb2CT(z) film. The present work therefore demonstrates that one fruitful approach to alter the electronic and optical properties of MXenes is to change the nature of the transition metal.
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| 9. |
- Halim, Joseph, et al.
(författare)
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Sodium hydroxide and vacuum annealing modifications of the surface terminations of a Ti3C2 (MXene) epitaxial thin film
- 2018
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Ingår i: RSC Advances. - : ROYAL SOC CHEMISTRY. - 2046-2069. ; 8:64, s. 36785-36790
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Tidskriftsartikel (refereegranskat)abstract
- We investigate, and quantify, changes in structure and surface terminations of epitaxial thin films of titanium carbide (Ti3C2) MXene, when treated by sodium hydroxide solution followed by vacuum annealing at 550 degrees C. Using X-ray photoelectron spectroscopy and scanning transmission electron microscopy, we show that NaOH treatment produce an increase in the c-lattice parameter together with an increase in the O terminations and a decrease in the F terminations. There is also an increase in the percentage of the binding energy of Ti-species in Ti 2p XPS region, which suggests an increase in the overall oxidation state of Ti. After subsequent annealing, the c-lattice parameter is slightly reduced, the overall oxidation state of Ti is decreased, and the F surface terminations are further diminished, leaving a surface with predominantly O as the surface terminating species. It is important to note that NaOH treatment facilitates removal of F at lower annealing temperatures than previously reported, which in turn is important for the range of attainable properties.
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| 10. |
- Muratov, Dmitry S., et al.
(författare)
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Slot-Die-Printed Two-Dimensional ZrS3 Charge Transport Layer for Perovskite Light-Emitting Diodes
- 2019
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Ingår i: ACS Applied Materials and Interfaces. - : AMER CHEMICAL SOC. - 1944-8244 .- 1944-8252. ; 11:51, s. 48021-48028
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Tidskriftsartikel (refereegranskat)abstract
- Liquid-phase exfoliation of zirconium trisulfide (ZrS3) was used to produce stable and ready-to-use inks for solution-processed semiconductor thin-film deposition. Ribbon-like layered crystals of ZrS3 were produced by the chemical vapor transport method and were then exfoliated in three different solvents: dimethylformamide, ethanol, and isopropyl alcohol. The resulting ZrS3 dispersions were compared for stability and the ability to form continuous films on top of the perovskite layer in light-emitting diodes with the ITO/PEDOT:PSS/MAPbBr(3)/2D-ZrS3/LiF/Al structure. Film deposition was performed by using either spray or slot-die coating methods. The slot-die coating route proved to produce better and more uniform films with respect to spray coating. We found that the 2D ZrS3 electron injection layer (EIL) stabilized the interface between the perovskite and LiF/Al cathode, reducing the turn-on voltage to 2.8 V and showing a luminance that does not degrade during voltage sweep. On the other hand, ELL-free devices show electroluminescence on the first voltage sweep that reduces almost to zero in the subsequent sweeps. Combining physical device simulation and density functional theory calculation, we are able to explain these results in terms of lowering the electron injection barrier at the cathode.
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