Change search
Refine search result
12345 151 - 200 of 229
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 151.
    Mozuraitis, Raimondas
    et al.
    Stockholm University, Faculty of Science, Department of Zoology. Nature Research Centre, Lithuania.
    Murtazina, Rushana
    Zurita, Javier
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Pei, Yuxin
    Ilag, Leopold
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Wiklund, Christer
    Stockholm University, Faculty of Science, Department of Zoology.
    Borg Karlson, Anna Karin
    Anti-aphrodisiac pheromone, a renewable signal in adult butterflies2019In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 9, article id 14262Article in journal (Refereed)
    Abstract [en]

    The male butterfly Pieris napi produces the anti-aphrodisiac pheromone methyl salicylate (MeS) and transfers it to the female during mating. After mating she releases MeS, when courted by conspecific males, which decreases her attractiveness and the duration of male harassment, thus increasing her time available for egg-laying. In previous studies we have shown that males produced MeS from the amino acid L-phenylalanine (L-Phe) acquired during larval stage. In this study we show that adult males of P. napi can utilize L-Phe and aromatic flower volatiles as building blocks for production of anti-aphrodisiac pheromone and transfer it to females during mating. We demonstrate this by feeding butterflies with stable isotope labelled molecules mixed in sugar solutions, and, to mimic the natural conditions, we fed male butterflies with floral nectar of Bunias orientalis plants treated with labelled L-Phe. The volatiles from butterflies and plants were collected and identified by solid phase micro extraction, gas chromatography and mass spectrometry techniques. Since P. napi is polygamous, males would gain from restoring the titre of MeS after mating and the use of aromatic precursors for production of MeS could be considered as an advantageous trait which could enable butterflies to relocate L-Phe for other needs.

  • 152.
    Muheim, Claudio
    et al.
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Götzke, Hansjörg
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Eriksson, Anna U.
    Lindberg, Stina
    Lauritsen, Ida
    Norholm, Morten H. H.
    Daley, Daniel O.
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Increasing the permeability of Escherichia coli using MAC132432017In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, article id 17629Article in journal (Refereed)
    Abstract [en]

    The outer membrane of gram-negative bacteria is a permeability barrier that prevents the efficient uptake of molecules with large scaffolds. As a consequence, a number of antibiotic classes are ineffective against gram-negative strains. Herein we carried out a high throughput screen for small molecules that make the outer membrane of Escherichia coli more permeable. We identified MAC13243, an inhibitor of the periplasmic chaperone LolA that traffics lipoproteins from the inner to the outer membrane. We observed that cells were (1) more permeable to the fluorescent probe 1-N-phenylnapthylamine, and (2) more susceptible to large-scaffold antibiotics when sub-inhibitory concentrations of MAC13243 were used. To exclude the possibility that the permeability was caused by an off-target effect, we genetically reconstructed the MAC13243-phenotype by depleting LolA levels using the CRISPRi system.

  • 153. Mörner, Torsten
    et al.
    Hansson, Tomas
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Carlsson, Le
    Berg, Anna-Lena
    Ruiz Muñoz, Yolanda
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. University of Vigo, Spain.
    Gustavsson, Hanna
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Mattsson, Roland
    Balk, Lennart
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Thiamine deficiency impairs common eider (Somateria mollissima) reproduction in the field2017In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, article id 14451Article in journal (Refereed)
    Abstract [en]

    The Baltic Sea population of the common eider (Somateria mollissima) has declined dramatically during the last two decades. Recently, widespread episodic thiamine (vitamin B1) deficiency has been demonstrated in feral birds and suggested to contribute significantly to declining populations. Here we show that the decline of the common eider population in the Baltic Sea is paralleled by high mortality of the pulli a few days after hatch, owing to thiamine deficiency and probably also thereby associated abnormal behaviour resulting in high gull predation. An experiment with artificially incubated common eider eggs collected in the field revealed that thiamine treatment of pulli had a therapeutic effect on the thiamine status of the brain and prevented death. The mortality was 53% in untreated specimens, whereas it was only 7% in thiamine treated specimens. Inability to dive was also linked to brain damage typical for thiamine deficiency. Our results demonstrate how thiamine deficiency causes a range of symptoms in the common eider pulli, as well as massive die-offs a few days after hatch, which probably are the major explanation of the recent dramatic population declines.

  • 154. Nahar, Nurun
    et al.
    Westerberg, Erik
    Arif, Usman
    Huchelmann, Alexandre
    Guasca, Alexandra Olarte
    Beste, Lisa
    Dalman, Kerstin
    Dutta, Paresh C.
    Jonsson, Lisbeth
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Sitbon, Folke
    Transcript profiling of two potato cultivars during glycoalkaloid-inducing treatments shows differential expression of genes in sterol and glycoalkaloid metabolism2017In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, article id 43268Article in journal (Refereed)
    Abstract [en]

    Steroidal glycoalkaloids (SGA) are sterol-derived neurotoxic defence substances present in several members of the Solanaceae. In the potato (Solanum tuberosum), high SGA levels may render tubers harmful for consumption. Tuber SGA levels depend on genetic factors, and can increase as a response to certain stresses and environmental conditions. To identify genes underlying the cultivar variation in tuber SGA levels, we investigated two potato cultivars differing in their SGA accumulation during wounding or light exposure; two known SGA-inducing treatments. Using microarray analysis coupled to sterol and SGA quantifications, we identified a small number of differentially expressed genes that were associated with increased SGA levels. Two of these genes, encoding distinct types of sterol Delta(24)-reductases, were by sense/antisense expression in transgenic potato plants shown to have differing roles in sterol and SGA metabolism. The results show that an increased SGA level in potato tubers during both wounding and light exposure is mediated by coordinated expression of a set of key genes in isoprenoid and steroid metabolism, and suggest that differences in this expression underlie cultivar variations in SGA levels. These results may find use within potato breeding and quality assessment.

  • 155.
    Nascimento, Francisco J. A.
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences. Bangor University, United Kingdom.
    Lallias, Delphine
    Bik, Holly M.
    Creer, Simon
    Sample size effects on the assessment of eukaryotic diversity and community structure in aquatic sediments using high-throughput sequencing2018In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, article id 11737Article in journal (Refereed)
    Abstract [en]

    Understanding how biodiversity changes in time and space is vital to assess the effects of environmental change on benthic ecosystems. Due to the limitations of morphological methods, there has been a rapid expansion in the application of high-throughput sequencing methods to study benthic eukaryotic communities. However, the effect of sample size and small-scale spatial variation on the assessment of benthic eukaryotic diversity is still not well understood. Here, we investigate the effect of different sample volumes in the genetic assessment of benthic metazoan and non-metazoan eukaryotic community composition. Accordingly, DNA was extracted from five different cumulative sediment volumes comprising 100% of the top 2 cm of five benthic sampling cores, and used as template for Ilumina MiSeq sequencing of 18 S rRNA amplicons. Sample volumes strongly impacted diversity metrics for both metazoans and non-metazoan eukaryotes. Beta-diversity of treatments using smaller sample volumes was significantly different from the beta-diversity of the 100% sampled area. Overall our findings indicate that sample volumes of 0.2 g (1% of the sampled area) are insufficient to account for spatial heterogeneity at small spatial scales, and that relatively large percentages of sediment core samples are needed for obtaining robust diversity measurement of both metazoan and non-metazoan eukaryotes.

  • 156.
    Nawareg, Mohamed
    et al.
    Stockholm University, Faculty of Science, Department of Physics. University of Gdansk, Poland.
    Muhammad, Sadiq
    Stockholm University, Faculty of Science, Department of Physics.
    Amselem, Elias
    Stockholm University, Faculty of Science, Department of Physics.
    Bourennane, Mohamed
    Stockholm University, Faculty of Science, Department of Physics.
    Experimental Measurement-Device-Independent Entanglement Detection2015In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 5, article id 8048Article in journal (Refereed)
    Abstract [en]

    Entanglement is one of the most puzzling features of quantum theory and of great importance for the new field of quantum information. The determination whether a given state is entangled or not is one of the most challenging open problems of the field. Here we report on the experimental demonstration of measurement-device-independent (MDI) entanglement detection using witness method for general two qubits photon polarization systems. In the MDI settings, there is no requirement to assume perfect implementations or neither to trust the measurement devices. This experimental demonstration can be generalized for the investigation of properties of quantum systems and for the realization of cryptography and communication protocols.

  • 157.
    Neagu, Alexandra
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Tai, Cheuk-Wai
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Local disorder in Na0.5Bi0.5TiO3-piezoceramic determined by 3D electron diffuse scattering2017In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, article id 12519Article in journal (Refereed)
    Abstract [en]

    Local structural distortions in Na0.5Bi0.5TiO3-based solid solutions have been proved to play a crucial role in understanding and tuning their enhanced piezoelectric properties near the morphotropic phase boundary. In this work all local structural disorders in a lead-free ternary system, namely 85% Na0.5Bi0.5TiO3-10% Bi0.5K0.5TiO3-5% BaTiO3, were mapped in reciprocal space by 3D electron diffraction. Furthermore, a comprehensive model of the local disorder was developed by analysing the intensity and morphology of the observed weak diffuse scattering. We found that the studied ceramics consists of plate-like in-phase oxygen octahedral nanoscale domains randomly distributed in an antiphase tilted matrix. In addition, A-site chemical short-range order of Na/Bi and polar displacements contribute to different kinds of diffuse scattering. The proposed model explains all the observed diffraction features and offers insight into the ongoing controversy over the nature of local structural distortions in Na0.5Bi0.5TiO3-based solid solutions.

  • 158. Nielsen, Steffen
    et al.
    Bassler, Niels
    Stockholm University, Faculty of Science, Department of Physics.
    Grzanka, Leszek
    Swakon, Jan
    Olko, Pawel
    Andreassen, Christian Nicolaj
    Alsner, Jan
    Sørensen, Brita Singers
    Optimal reference genes for normalization of qPCR gene expression data from proton and photon irradiated dermal fibroblasts2018In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, article id 12688Article in journal (Refereed)
    Abstract [en]

    The transcriptional response of cells exposed to proton radiation is not equivalent to the response induced by traditional photon beams. Changes in cellular signalling is most commonly studied using the method Quantitative polymerase chain reaction (qPCR). Stable reference genes must be used to accurately quantify target transcript expression. The study aim was to identify suitable reference genes for normalisation of gene expression levels in normal dermal fibroblasts irradiated with either proton or photon beams. The online tool RefFinder was used to analyse and identify the most stably expressed genes from a panel of 22 gene candidates. To assess the reliability of the identified reference genes, a selection of the most and least stable reference genes was used to normalise target transcripts of interest. Fold change levels varied considerably depending on the used reference gene. The top ranked genes IPO8, PUM1, MRPL19 and PSMC4 produced highly similar target gene expression, while expression using the worst ranked genes, TFRC and HPRT1, was clearly modified due to reference gene instability.

  • 159.
    Nilsonne, Gustav
    et al.
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet, Sweden .
    Tamm, Sandra
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet, Sweden .
    Schwarz, Johanna
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet, Sweden .
    Almeida, Rita
    Fischer, Håkan
    Stockholm University, Faculty of Social Sciences, Department of Psychology, Biological psychology.
    Kecklund, Göran
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Lekander, Mats
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet, Sweden .
    Fransson, Peter
    Åkerstedt, Torbjörn
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet, Sweden .
    Intrinsic brain connectivity after partial sleep deprivation in young and older adults: results from the Stockholm Sleepy Brain study2017In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, article id 9422Article in journal (Refereed)
    Abstract [en]

    Sleep deprivation has been reported to affect intrinsic brain connectivity, notably reducing connectivity in the default mode network. Studies to date have however shown inconsistent effects, in many cases lacked monitoring of wakefulness, and largely included young participants. We investigated effects of sleep deprivation on intrinsic brain connectivity in young and older participants. Participants aged 20–30 (final n = 30) and 65–75 (final n = 23) years underwent partial sleep deprivation (3 h sleep) in a cross-over design, with two 8-minutes eyes-open resting state functional magnetic resonance imaging (fMRI) runs in each session, monitored by eye-tracking. We assessed intrinsic brain connectivity using independent components analysis (ICA) as well as seed-region analyses of functional connectivity, and also analysed global signal variability, regional homogeneity, and the amplitude of low-frequency fluctuations. Sleep deprivation caused increased global signal variability. Changes in investigated resting state networks and in regional homogeneity were not statistically significant. Younger participants had higher connectivity in most examined networks, as well as higher regional homogeneity in areas including anterior and posterior cingulate cortex. In conclusion, we found that sleep deprivation caused increased global signal variability, and we speculate that this may be caused by wake-state instability.

  • 160.
    Nilsson, Tobias
    et al.
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Rydström Lundin, Camilla
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Nordlund, Gustav
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Ädelroth, Pia
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    von Ballmoos, Christoph
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics. University of Bern, Switzerland.
    Brzezinski, Peter
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Lipid-mediated Protein-protein Interactions Modulate Respiration-driven ATP Synthesis2016In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 6, article id 24113Article in journal (Refereed)
    Abstract [en]

    Energy conversion in biological systems is underpinned by membrane-bound proton transporters that generate and maintain a proton electrochemical gradient across the membrane which used, e.g. for generation of ATP by the ATP synthase. Here, we have co-reconstituted the proton pump cytochrome bo3 (ubiquinol oxidase) together with ATP synthase in liposomes and studied the effect of changing the lipid composition on the ATP synthesis activity driven by proton pumping. We found that for 100 nm liposomes, containing 5 of each proteins, the ATP synthesis rates decreased significantly with increasing fractions of DOPA, DOPE, DOPG or cardiolipin added to liposomes made of DOPC; with e.g. 5% DOPG, we observed an almost 50% decrease in the ATP synthesis rate. However, upon increasing the average distance between the proton pumps and ATP synthases, the ATP synthesis rate dropped and the lipid dependence of this activity vanished. The data indicate that protons are transferred along the membrane, between cytochrome bo3 and the ATP synthase, but only at sufficiently high protein densities. We also argue that the local protein density may be modulated by lipid-dependent changes in interactions between the two proteins complexes, which points to a mechanism by which the cell may regulate the overall activity of the respiratory chain.

  • 161.
    Nyqvist, Ida
    et al.
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Dogan, Jakob
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Characterization of the dynamics and the conformational entropy in the binding between TAZ1 and CTAD-HIF-1α2019In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 9, article id 16557Article in journal (Refereed)
    Abstract [en]

    The interaction between the C-terminal transactivation domain of HIF-1α (CTAD-HIF-1α) and the transcriptional adapter zinc binding 1 (TAZ1) domain of CREB binding protein participate in the initiation of gene transcription during hypoxia. Unbound CTAD-HIF-1α is disordered but undergoes a disorder-to-order transition upon binding to TAZ1. We have here performed NMR side chain and backbone relaxation studies on TAZ1 and side chain relaxation measurements on CTAD-HIF-1α in order to investigate the role of picosecond to nanosecond dynamics. We find that the internal motions are significantly affected upon binding, both on the side chain and the backbone level. The dynamic response corresponds to a conformational entropy change that contributes substantially to the binding thermodynamics for both binding partners. Furthermore, the conformational entropy change for the well-folded TAZ1 varies upon binding to different IDP targets. We further identify a cluster consisting of side chains in bound TAZ1 and CTAD-HIF-1α that experience extensive dynamics and are part of the binding region that involves the N-terminal end of the LPQL motif in CTAD-HIF-1α; a feature that might have an important role in the termination of the hypoxic respons

  • 162.
    Olenius, Tinja
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Pichelstorfer, Lukas
    Stolzenburg, Dominik
    Winkler, Paul M.
    Lehtinen, Kari E. J.
    Riipinen, Ilona
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Robust metric for quantifying the importance of stochastic effects on nanoparticle growth2018In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, article id 14160Article in journal (Refereed)
    Abstract [en]

    Comprehensive representation of nanoparticle dynamics is necessary for understanding nucleation and growth phenomena. This is critical in atmospheric physics, as airborne particles formed from vapors have significant but highly uncertain effects on climate. While the vapor-particle mass exchange driving particle growth can be described by a macroscopic, continuous substance for large enough particles, the growth dynamics of the smallest nanoparticles involve stochastic fluctuations in particle size due to discrete molecular collision and decay processes. To date, there have been no generalizable methods for quantifying the particle size regime where the discrete effects become negligible and condensation models can be applied. By discrete simulations of sub-10 nm particle populations, we demonstrate the importance of stochastic effects in the nanometer size range. We derive a novel, theory-based, simple and robust metric for identifying the exact sizes where these effects cannot be omitted for arbitrary molecular systems. The presented metric, based on examining the second- and first-order derivatives of the particle size distribution function, is directly applicable to experimental size distribution data. This tool enables quantifying the onset of condensational growth without prior information on the properties of the vapors and particles, thus allowing robust experimental resolving of nanoparticle formation physics.

  • 163. Pace, Aurélie
    et al.
    Bourillot, Raphael
    Bouton, Anthony
    Vennin, Emmanuelle
    Galaup, Serge
    Bundeleva, Irina
    Patrier, Patricia
    Dupraz, Christophe
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Thomazo, Christophe
    Sansjofre, Pierre
    Yokoyama, Yusuke
    Franceschi, Michel
    Anguy, Yannick
    Pigot, Lea
    Virgone, Aurelien
    Visscher, Pieter T.
    Microbial and diagenetic steps leading to the mineralisation of Great Salt Lake microbialites2016In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 6, article id 31495Article in journal (Refereed)
    Abstract [en]

    Microbialites are widespread in modern and fossil hypersaline environments, where they provide a unique sedimentary archive. Authigenic mineral precipitation in modern microbialites results from a complex interplay between microbial metabolisms, organic matrices and environmental parameters. Here, we combined mineralogical and microscopic analyses with measurements of metabolic activity in order to characterise the mineralisation of microbial mats forming microbialites in the Great Salt Lake (Utah, USA). Our results show that the mineralisation process takes place in three steps progressing along geochemical gradients produced through microbial activity. First, a poorly crystallized Mg-Si phase precipitates on alveolar extracellular organic matrix due to a rise of the pH in the zone of active oxygenic photosynthesis. Second, aragonite patches nucleate in close proximity to sulfate reduction hotspots, as a result of the degradation of cyanobacteria and extracellular organic matrix mediated by, among others, sulfate reducing bacteria. A final step consists of partial replacement of aragonite by dolomite, possibly in neutral to slightly acidic porewater. This might occur due to dissolution-precipitation reactions when the most recalcitrant part of the organic matrix is degraded. The mineralisation pathways proposed here provide pivotal insight for the interpretation of microbial processes in past hypersaline environments.

  • 164. Paris-Mandoki, A.
    et al.
    Shearring, J.
    Mancarella, Francesco
    Stockholm University, Nordic Institute for Theoretical Physics (Nordita).
    Fromhold, T. M.
    Trombettoni, A.
    Krüger, P.
    Superfluid flow above the critical velocity2017In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, article id 9070Article in journal (Refereed)
    Abstract [en]

    Superfluidity and superconductivity have been widely studied since the last century in many different contexts ranging from nuclear matter to atomic quantum gases. The rigidity of these systems with respect to external perturbations results in frictionless motion for superfluids and resistance-free electric current flow in superconductors. This peculiar behaviour is lost when external perturbations overcome a critical threshold, i.e. above a critical magnetic field or a critical current for superconductors. In superfluids, such as liquid helium or ultracold gases, the corresponding quantities are a critical rotation rate and a critical velocity respectively. Enhancing the critical values is of great fundamental and practical value. Here we demonstrate that superfluidity can be completely restored for specific, arbitrarily large flow velocities above the critical velocity through quantum interference-induced resonances providing a nonlinear counterpart of the Ramsauer-Townsend effect occurring in ordinary quantum mechanics. We illustrate the robustness of this phenomenon through a thorough analysis in one dimension and prove its generality by showing the persistence of the effect in non-trivial 2d systems. This has far reaching consequences for the fundamental understanding of superfluidity and superconductivity and opens up new application possibilities in quantum metrology, e.g. in rotation sensing.

  • 165. Peralta-Maraver, Ignacio
    et al.
    Galloway, Jason
    Posselt, Malte
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Arnon, Shai
    Reiss, Julia
    Lewandowski, Joerg
    Robertson, Anne L.
    Environmental filtering and community delineation in the streambed ecotone2018In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, article id 15871Article in journal (Refereed)
    Abstract [en]

    A current controversy in ecology is whether biological communities are discrete biological entities or simply study units created for convenience; a debate that becomes even more heated when delimiting communities along ecotones. Here, we report an interdisciplinary study designed to address the interplay between environmental drivers and community ecology in a typical ecotone ecosystem: the streambed. Environmental filtering at a micro-scale determined how diversity, productivity and composition of the whole streambed assemblage varied with depth and with the direction of vertical water exchange. Biomass and production decreased with increasing depth, and were lower under upwelling than downwelling conditions. However, the rate at which biomass and production decreased with increasing depth differed significantly for different taxonomic groups. Using quantitative biocenosis analysis, we also showed that benthic and hyporheic zone assemblages (assemblages in close juxtaposition) could be clearly distinguished as discrete communities with individual integrity. Vertical hydrodynamic conditions also influenced the demarcation between both communities; the benthic community reached greater depths in downwelling than in upwelling zones.

  • 166. Persoiu, Aurel
    et al.
    Onac, Bogdan P.
    Wynn, Jonathan G.
    Blaauw, Maarten
    Ionita, Monica
    Hansson, Margareta
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Holocene winter climate variability in Central and Eastern Europe2017In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, article id 1196Article in journal (Refereed)
    Abstract [en]

    Among abundant reconstructions of Holocene climate in Europe, only a handful has addressed winter conditions, and most of these are restricted in length and/or resolution. Here we present a record of late autumn through early winter air temperature and moisture source changes in East-Central Europe for the Holocene, based on stable isotopic analysis of an ice core recovered from a cave in the Romanian Carpathian Mountains. During the past 10,000 years, reconstructed temperature changes followed insolation, with a minimum in the early Holocene, followed by gradual and continuous increase towards the mid-to-late-Holocene peak (between 4-2 kcal BP), and finally by a decrease after 0.8 kcal BP towards a minimum during the Little Ice Age (AD 1300-1850). Reconstructed early Holocene atmospheric circulation patterns were similar to those characteristics of the negative phase of the North Atlantic Oscillation (NAO), while in the late Holocene they resembled those prevailing in the positive NAO phase. The transition between the two regimes occurred abruptly at around 4.7 kcal BP. Remarkably, the widespread cooling at 8.2 kcal BP is not seen very well as a temperature change, but as a shift in moisture source, suggesting weaker westerlies and increased Mediterranean cyclones penetrating northward at this time.

  • 167. Petoukhov, Vladimir
    et al.
    Petri, Stefan
    Kornhuber, Kai
    Thonicke, Kirsten
    Coumou, Dim
    Schellnhuber, Hans Joachim
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. Potsdam Institute for Climate Impact Research (PIK), Germany.
    Alberta wildfire 2016: Apt contribution from anomalous planetary wave dynamics2018In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, article id 12375Article in journal (Refereed)
    Abstract [en]

    In May-June 2016 the Canadian Province of Alberta suffered one of the most devastating wildfires in its history. Here we show that in mid-April to early May 2016 the large-scale circulation in the mid-and high troposphere of the middle and sub-polar latitudes of the northern hemisphere featured a persistent high-amplitude planetary wave structure dominated by the non-dimensional zonal wave number 4. The strongest anticyclonic wing of this structure was located over western Canada. In combination with a very strong El Nino event in winter 2015/2016 this favored highly anomalous, tinder-dry and high-temperature conditions at the surface in that area, entailing an increased fire hazard there. This critically contributed to the ignition of the Alberta Wildfire in May 2016, appearing to be the costliest disaster in Canadian history thus far.

  • 168. Petrini, Michele
    et al.
    Colleoni, Florence
    Kirchner, Nina
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Hughes, Anna L. C.
    Camerlenghi, Angelo
    Rebesco, Michele
    Lucchi, Renata G.
    Forte, Emanuele
    Colucci, Renato R.
    Noormets, Riko
    Interplay of grounding-line dynamics and sub-shelf melting during retreat of the Bjornoyrenna Ice Stream2018In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, article id 7196Article in journal (Refereed)
    Abstract [en]

    The Barents Sea Ice Sheet was a marine-based ice sheet, i.e., it rested on the Barents Sea floor during the Last Glacial Maximum (21 ky BP). The Bjornoyrenna Ice Stream was the largest ice stream draining the Barents Sea Ice Sheet and is regarded as an analogue for contemporary ice streams in West Antarctica. Here, the retreat of the Bjornoyrenna Ice Stream is simulated by means of two numerical ice sheet models and results assessed against geological data. We investigate the sensitivity of the ice stream to changes in ocean temperature and the impact of grounding-line physics on ice stream retreat. Our results suggest that the role played by sub-shelf melting depends on how the grounding-line physics is represented in the models. When an analytic constraint on the ice flux across the grounding line is applied, the retreat of Bjornoyrenna Ice Stream is primarily driven by internal ice dynamics rather than by oceanic forcing. This suggests that implementations of grounding-line physics need to be carefully assessed when evaluating and predicting the response of contemporary marine-based ice sheets and individual ice streams to ongoing and future ocean warming.

  • 169.
    Pečnerová, Patrícia
    et al.
    Stockholm University, Faculty of Science, Department of Zoology. Swedish Museum of Natural History, Sweden.
    Diez-del-Molino, David
    Vartanyan, Sergey
    Dalén, Love
    Changes in variation at the MHC class II DQA locus during the final demise of the woolly mammoth2016In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 6, article id 25274Article in journal (Refereed)
    Abstract [en]

    According to the nearly-neutral theory of evolution, the relative strengths of selection and drift shift in favour of drift at small population sizes. Numerous studies have analysed the effect of bottlenecks and small population sizes on genetic diversity in the MHC, which plays a central role in pathogen recognition and immune defense and is thus considered a model example for the study of adaptive evolution. However, to understand changes in genetic diversity at loci under selection, it is necessary to compare the genetic diversity of a population before and after the bottleneck. In this study, we analyse three fragments of the MHC DQA gene in woolly mammoth samples radiocarbon dated to before and after a well-documented bottleneck that took place about ten thousand years ago. Our results indicate a decrease in observed heterozygosity and number of alleles, suggesting that genetic drift had an impact on the variation on MHC. Based on coalescent simulations, we found no evidence of balancing selection maintaining MHC diversity during the Holocene. However, strong trans-species polymorphism among mammoths and elephants points to historical effects of balancing selection on the woolly mammoth lineage.

  • 170.
    Piech, Richard M.
    et al.
    Stockholm University, Faculty of Social Sciences, Department of Psychology, Perception and psychophysics. Anglia Ruskin University, UK.
    Strelchuk, Daniela
    Knights, Jake
    Hjälmheden, Jonathan V.
    Stockholm University, Faculty of Social Sciences, Department of Psychology.
    Olofsson, Jonas K.
    Stockholm University, Faculty of Social Sciences, Department of Psychology, Perception and psychophysics.
    Aspell, Jane E.
    People with higher interoceptive sensitivity are more altruistic, but improving interoception does not increase altruism2017In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, article id 15652Article in journal (Refereed)
    Abstract [en]

    People consistently show preferences and behaviors that benefit others at a cost to themselves, a phenomenon termed altruism. We investigated if perception of one's body signals - interoception - may be underlying such behaviors. We tested if participants' sensitivity to their own heartbeat predicted their decision on a choice between self-interest and altruism, and if improving this sensitivity through training would make participants more altruistic. Across these two experiments, interoceptive sensitivity predicted altruism measured through monetary generosity. Improving interoceptive sensitivity did, however, not lead to more altruistic behaviour. We conclude that there is a unique link between interoception and altruistic behaviour, likely established over an individual's history of altruistic acts, and the body responses they elicit. The findings suggest that humans might literally 'listen to their heart' to guide their altruistic behavior.

  • 171. Poletti, Sophia C.
    et al.
    Cavazzana, Annachiara
    Stockholm University, Faculty of Social Sciences, Department of Psychology, Perception and psychophysics. Technische Universität Dresden, Germany.
    Guducu, Cagdas
    Larsson, Maria
    Stockholm University, Faculty of Social Sciences, Department of Psychology, Perception and psychophysics.
    Hummel, Thomas
    Indistinguishable odour enantiomers: Differences between peripheral and central-nervous electrophysiological responses2017In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, article id 8978Article in journal (Refereed)
    Abstract [en]

    The ability of humans to discriminate enantiomeric odour pairs is substance-specific. Current literature suggests that psychophysical discrimination of odour enantiomers mainly depends on the peripheral processing at the level of the olfactory sensory neurons (OSN). To study the influence of central processing in discrimination, we investigated differences in the electrophysiological responses to psychophysically indistinguishable (+)- and (-)- rose oxide enantiomers at peripheral and central-nervous levels in humans. We recorded the electro-olfactogram (EOG) from the olfactory epithelium and the EEG-derived olfactory event-related potentials (OERP). Results from a psychophysical three alternative forced choice test indicated indistinguishability of the two odour enantiomers. In a total of 19 young participants EOG could be recorded in 74 and OERP in 95% of subjects. Significantly different EOG amplitudes and latencies were recorded in response to the 2 stimuli. However, no such differences in amplitude or latency emerged for the OERP. In conclusion, although the pair of enantiomer could be discriminated at a peripheral level this did not lead to a central-nervous/cognitive differentiation of the two stimuli.

  • 172. Polido Legaria, Elizabeth
    et al.
    Rocha, Joao
    Tai, Cheuk-Wai
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Kessler, Vadim G.
    Seisenbaeva, Gulaim A.
    Unusual seeding mechanism for enhanced performance in solid-phase magnetic extraction of Rare Earth Elements2017In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, article id 43740Article in journal (Refereed)
    Abstract [en]

    Due to the increasing demand of Rare Earth Elements (REE or RE), new and more efficient techniques for their extraction are necessary, suitable for both mining and recycling processes. Current techniques such as solvent extraction or solid adsorbents entail drawbacks such as using big volumes of harmful solvents or limited capacity. Hybrid nanoadsorbents based on SiO2 and highly stable gamma-Fe2O3-SiO2 nanoparticles, proved recently to be very attractive for adsorption of REE, yet not being the absolute key to solve the problem. In the present work, we introduce a highly appealing new approach in which the nanoparticles, rather than behaving as adsorbent materials, perform as inducers of crystallization for the REE in the form of hydroxides, allowing their facile and practically total removal from solution. This induced crystallization is achieved by tuning the pH, offering an uptake efficiency more than 20 times higher than previously reported (up to 900 mg RE3+/g vs. 40 mg RE3+/g). The obtained phases were characterized by SEM-EDS, TEM, STEM and EFTEM and C-13 and Si-29 solid state NMR. Magnetic studies showed that the materials possessed enough magnetic properties to be easily removed by a magnet, opening ways for an efficient and industrially applicable separation technique.

  • 173. Pontén, Moa
    et al.
    Fust, Jens
    D'Onofrio, Paolo
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    van Dorp, Rick
    Stockholm University, Faculty of Social Sciences, Stress Research Institute.
    Sunnergård, Linda
    Ingre, Michael
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Institute for Globally Distributed Open Research and Education (IGDORE), Sweden.
    Axelsson, John
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet, Sweden.
    Jensen, Karin
    The pain alarm response - an example of how conscious awareness shapes pain perception2019In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 9, article id 12478Article in journal (Refereed)
    Abstract [en]

    Pain is subjective and largely shaped by context, yet, little is known about the boundaries for such influences, in particular in relation to conscious awareness. Here, we investigated processing of noxious stimuli during sleep. Four experiments were performed where participants (n = 114) were exposed to repetitions of noxious heat, either when awake or during sleep. A test-phase followed where participants were awake and exposed to painful stimuli and asked to rate pain. Two control experiments included only the test-phase, without any prior pain exposures. Participants in the awake condition rated all test-phase stimuli the same. Conversely, participants who had been sleeping, and thus unaware of getting noxious heat, displayed heightened pain during the first part of the test-phase. This heightened reaction to noxious stimuli-a pain alarm response-was further pronounced in the control conditions where participants were naive to noxious heat. Results suggest that the pain alarm response is partly dependent on conscious awareness.

  • 174. Procaccini, Gabriele
    et al.
    Ruocco, Miriam
    Marin-Guirao, Lazaro
    Dattolo, Emanuela
    Brunet, Christophe
    D'Esposito, Daniela
    Lauritano, Chiara
    Mazzuca, Silvia
    Serra, Ilia Anna
    Bernardo, Letizia
    Piro, Amalia
    Beer, Sven
    Björk, Mats
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Gullström, Martin
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Buapet, Pimchanok
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences. Prince of Songkla University, Thailand.
    Rasmusson, Lina M.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Felisberto, Paulo
    Gobert, Sylvie
    Runcie, John W.
    Silva, Joao
    Olive, Irene
    Costa, Monya M.
    Barrote, Isabel
    Santos, Rui
    Depth-specific fluctuations of gene expression and protein abundance modulate the photophysiology in the seagrass Posidonia oceanica2017In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, article id 42890Article in journal (Refereed)
    Abstract [en]

    Here we present the results of a multiple organizational level analysis conceived to identify acclimative/adaptive strategies exhibited by the seagrass Posidonia oceanica to the daily fluctuations in the light environment, at contrasting depths. We assessed changes in photophysiological parameters, leaf respiration, pigments, and protein and mRNA expression levels. The results show that the diel oscillations of P. oceanica photophysiological and respiratory responses were related to transcripts and proteins expression of the genes involved in those processes and that there was a response asynchrony between shallow and deep plants probably caused by the strong differences in the light environment. The photochemical pathway of energy use was more effective in shallow plants due to higher light availability, but these plants needed more investment in photoprotection and photorepair, requiring higher translation and protein synthesis than deep plants. The genetic differentiation between deep and shallow stands suggests the existence of locally adapted genotypes to contrasting light environments. The depth-specific diel rhythms of photosynthetic and respiratory processes, from molecular to physiological levels, must be considered in the management and conservation of these key coastal ecosystems.

  • 175.
    Rasmusson, Lina M.
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences. University of Gothenburg, Sweden.
    Gullström, Martin
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences. University of Gothenburg, Sweden.
    Gunnarsson, Pontus C. B.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    George, Rushingisha
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences. Tanzania Fisheries Research Institute (TAFIRI), Tanzania.
    Björk, Mats
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Estimation of a whole plant Q10 to assess seagrass productivity during temperature shifts2019In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 9, article id 12667Article in journal (Refereed)
    Abstract [en]

    Through respiration and photosynthesis, seagrass meadows contribute greatly to carbon and oxygen fluxes in shallow coastal waters. There is increasing concern about how shallow-water primary producers will react to a near-future climate scenario with increased temperature variation. When modelling primary productivity under high temperature variability, Q10 values are commonly used to predict rate changes depending on biophysical factors. Q10 values are often assumed to be constant and around 2.0 (i.e. a doubling of the rate with a temperature increase of 10 degrees C). We aimed to establish how the gas exchange of seagrass (Zostera marina) tissues at various maturity stages would respond over a broad range of temperatures. Seagrass shoot maturity stage clearly affected respiration and apparent photosynthesis, and the Q10 results indicated a skewed balance between the two processes, with a higher photosynthetic Q10 during periods of elevated temperatures. When estimating whole-plant Q10 in a realistic maximal temperature range, we found that the overall response of a seagrass plant's net O-2 exchange balance can be as much as three to four times higher than under ambient temperatures. Our findings indicate that plant tissue age and temperature should be considered when assessing and modelling carbon and oxygen fluctuations in vegetated coastal areas.

  • 176. Redin, David
    et al.
    Frick, Tobias
    Aghelpasand, Hooman
    Käller, Max
    Borgström, Erik
    Olsen, Remi-Andre
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics. Stockholm University, Science for Life Laboratory (SciLifeLab).
    Ahmadian, Afshin
    High throughput barcoding method for genome-scale phasing2019In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 9, article id 18116Article in journal (Refereed)
    Abstract [en]

    The future of human genomics is one that seeks to resolve the entirety of genetic variation through sequencing. The prospect of utilizing genomics for medical purposes require cost-efficient and accurate base calling, long-range haplotyping capability, and reliable calling of structural variants. Short-read sequencing has lead the development towards such a future but has struggled to meet the latter two of these needs. To address this limitation, we developed a technology that preserves the molecular origin of short sequencing reads, with an insignificant increase to sequencing costs. We demonstrate a novel library preparation method for high throughput barcoding of short reads where millions of random barcodes can be used to reconstruct megabase-scale phase blocks.

  • 177.
    Riboni, Nicoló
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. University of Parma, Italy.
    Quaranta, Alessandro
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Motwani, Hitesh
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Österlund, Nickles
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Gräslund, Astrid
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Bianchi, Federica
    Ilag, Leopold L.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Solvent-Assisted Paper Spray Ionization Mass Spectrometry (SAPSI-MS) for the Analysis of Biomolecules and Biofluids2019In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 9, article id 10296Article in journal (Refereed)
    Abstract [en]

    Paper Spray Ionization (PSI) is commonly applied for the analysis of small molecules, including drugs, metabolites, and pesticides in biological fluids, due to its high versatility, simplicity, and low costs. In this study, a new setup called Solvent Assisted Paper Spray Ionization (SAPSI), able to increase data acquisition time, signal stability, and repeatability, is proposed to overcome common PSI drawbacks. The setup relies on an integrated solution to provide ionization potential and constant solvent flow to the paper tip. Specifically, the ion source was connected to the instrument fluidics along with the voltage supply systems, ensuring a close control over the ionization conditions. SAPSI was successfully applied for the analysis of different classes of biomolecules: amyloidogenic peptides, proteins, and N-glycans. The prolonged analysis time allowed real-time monitoring of processes taking places on the paper tip, such as amyloid peptides aggregation and disaggregation phenomena. The enhanced signal stability allowed to discriminate protein species characterized by different post translational modifications and adducts with electrophilic compounds, both in aqueous solutions and in biofluids, such as serum and cerebrospinal fluid, without any sample pretreatment. In the next future, application to clinical relevant modifications, could lead to the development of quick and cost-effective diagnostic tools.

  • 178. Roy, Bitan
    et al.
    Juricic, Vladimir
    Stockholm University, Nordic Institute for Theoretical Physics (Nordita).
    Sarma, Sankar Das
    Universal optical conductivity of a disordered Weyl semimetal2016In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 6, article id 32446Article in journal (Refereed)
    Abstract [en]

    Topological Weyl semimetals, besides manifesting chiral anomaly, can also accommodate a disorder-driven unconventional quantum phase transition into a metallic phase. A fundamentally and practically important question in this regard concerns an experimentally measurable quantity that can clearly distinguish these two phases. We show that the optical conductivity while serving this purpose can also play the role of a bonafide order parameter across such disorder-driven semimetal-metal quantum phase transition by virtue of displaying distinct scaling behavior in the semimetallic and metallic phases, as well as inside the quantum critical fan supporting a non-Fermi liquid. We demonstrate that the correction to the dielectric constant and optical conductivity in a dirty Weyl semimetal due to weak disorder is independent of the actual nature of point-like impurity scatterers. Therefore, optical conductivity can be used as an experimentally measurable quantity to study the critical properties and to pin the universality class of the disorder-driven quantum phase transition in Weyl semimetals.

  • 179. Rybski, Diego
    et al.
    Buldyrev, Sergey V.
    Havlin, Shlomo
    Liljeros, Fredrik
    Stockholm University, Faculty of Social Sciences, Department of Sociology. Institute for Futures Studies, Sweden.
    Makse, Hernán A.
    Communication activity in a social network: relation between long-term correlations and inter-event clustering2012In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 2, article id 560Article in journal (Refereed)
    Abstract [en]

    Human communication in social networks is dominated by emergent statistical laws such as non-trivial correlations and temporal clustering. Recently, we found long-term correlations in the user's activity in social communities. Here, we extend this work to study the collective behavior of the whole community with the goal of understanding the origin of clustering and long-term persistence. At the individual level, we find that the correlations in activity are a byproduct of the clustering expressed in the power-law distribution of inter-event times of single users, i.e. short periods of many events are separated by long periods of no events. On the contrary, the activity of the whole community presents long-term correlations that are a true emergent property of the system, i.e. they are not related to the distribution of inter-event times. This result suggests the existence of collective behavior, possibly arising from nontrivial communication patterns through the embedding social network.

  • 180.
    Sajwan, Suresh
    et al.
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Mannervik, Mattias
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Gene activation by dCas9-CBP and the SAM system differ in target preference2019In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 9, article id 18104Article in journal (Refereed)
    Abstract [en]

    Gene overexpression through the targeting of transcription activation domains to regulatory DNA via catalytically defective Cas9 (dCas9) represents a powerful approach to investigate gene function as well as the mechanisms of gene control. To date, the most efficient dCas9-based activator is the Synergistic Activation Mediator (SAM) system whereby transcription activation domains are directly fused to dCas9 as well as tethered through MS2 loops engineered into the gRNA. Here, we show that dCas9 fused to the catalytic domain of the histone acetyltransferase CBP is a more potent activator than the SAM system at some loci, but less efficient at other locations in Drosophila cells. Our results suggest that different rate-limiting steps in the transcription cycle are affected by dCas9-CBP and the SAM system, and that comparing these activators may be useful for mechanistic studies of transcription as well as for increasing the number of hits in genome-wide overexpression screens.

  • 181. Salama, Suzy M.
    et al.
    Gwaram, Nura Suleiman
    AlRashdi, Ahmed S.
    Khalifa, Shaden A. M.
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute. Karolinska University Hospital, Sweden; Kumamoto University, Japan.
    Abdulla, Mahmood A.
    Ali, Hapipah M.
    El-Seedi, Hesham R.
    A Zinc Morpholine Complex Prevents HCl/Ethanol-Induced Gastric Ulcers in a Rat Model2016In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 6, article id 29646Article in journal (Refereed)
    Abstract [en]

    Zinc is a naturally occurring element with roles in wound healing and rescuing tissue integrity, particularly in the gastrointestinal system, where it can be detected in the mucosal and submucosal layers. Zinc chelates are known to have beneficial effects on the gastrointestinal mucosa and in cases of gastric ulcer. We synthesized complexes of zinc featuring a heterocyclic amine binding amino acids then investigated their ability to enhance the gastric self-repair. Zinc-morpholine complex, Zn(L)SCN, namely showed strong free-radical scavenging, promotion of the DNA and RNA polymerases reconstruction and suppression of cell damage. The complex's mode of action is proposed to involve hydrogen bond formation via its bis(thiocyanato-k) zinc moiety. Zn(L) SCN complex had potent effects on gastric enzymatic activity both in vitro and in vivo. The complex disrupted the ulcerative process as demonstrated by changes in the intermediate metabolites of the oxidative pathway - specifically, reduction in the MDA levels and elevation of reduced glutathione together with an attenuation of oxidative DNA damage. Additionally, Zn(L) SCN restored the gastric mucosa, inhibited the production of pro-inflammatory cytokines (IL-6, TNF and the caspases), and preserved the gastric mucous balance. Zn(L) SCN thus exhibited anti-oxidative, anti-inflammatory and anti-apoptotic activities, all of which have cytoprotective effects on the gastric lining.

  • 182.
    Samrani, George
    et al.
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI).
    Marklund, Petter
    Stockholm University, Faculty of Social Sciences, Department of Psychology, Cognitive psychology.
    Engström, Lisa
    Broman, Daniel
    Persson, Jonas
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI).
    Behavioral facilitation and increased brain responses from a high interference working memory context2018In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, article id 15308Article in journal (Refereed)
    Abstract [en]

    Many real-life situations require flexible behavior in changing environments. Evidence suggests that anticipation of conflict or task difficulty results in behavioral and neural allocation of task-relevant resources. Here we used a high-and low-interference version of an item-recognition task to examine the neurobehavioral underpinnings of context-sensitive adjustment in working memory (WM). We hypothesized that task environments that included high-interference trials would require participants to allocate neurocognitive resources to adjust to the more demanding task context. The results of two independent behavioral experiments showed enhanced WM performance in the high-interference context, which indicated that a high-interference context improves performance on non-interference trials. A third behavioral experiment showed that when WM load was increased, this effect was no longer significant. Neuroimaging results further showed greater engagement of inferior frontal gyrus, striatum, parietal cortex, hippocampus, and midbrain in participants performing the task in the high-than in the low-interference context. This effect could arise from an active or dormant mode of anticipation that seems to engage fronto-striatal and midbrain regions to flexibly adjust resources to task demands. Our results extend the model of conflict adaptation beyond trial-to-trial adjustments by showing that a high interference context affects both behavioral and biological aspects of cognition.

  • 183.
    Saroj, Sunil D.
    et al.
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Holmer, Linda
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Berengueras, Júlia M.
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Jonsson, Ann-Beth
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Inhibitory role of acyl homoserine lactones in hemolytic activity and viability of Streptococcus pyogenes M6 S1652017In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, article id 44902Article in journal (Refereed)
    Abstract [en]

    Streptococcus pyogenes an adapted human pathogen asymptomatically colonizes the nasopharynx, among other polymicrobial communities. However, information on the events leading to the colonization and expression of virulence markers subject to interspecies and host-bacteria interactions are limited. The interference of acyl homoserine lactones (AHLs) with the hemolytic activity and viability of S. pyogenes M6 S165 was examined. AHLs, with fatty acid side chains >= 12 carbon atoms, inhibited hemolytic activity by downregulating the expression of the sag operon involved in the production of streptolysin S. Inhibitory AHLs upregulated the expression of transcriptional regulator LuxR. Electrophoretic mobility shift assays revealed the interaction of LuxR with the region upstream of sagA. AHL-mediated bactericidal activity observed at higher concentrations (mM range) was an energydependent process, constrained by the requirement of glucose and iron. Ferrichrome transporter FtsABCD facilitated transport of AHLs across the streptococcal membrane. The study demonstrates a previously unreported role for AHLs in S. pyogenes virulence.

  • 184. Schleussner, Carl-Friedrich
    et al.
    Donges, Jonathan F.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. Potsdam Institute for Climate Impact Research, Germany.
    Engemann, Denis A.
    Levermann, Anders
    Clustered marginalization of minorities during social transitions induced by co-evolution of behaviour and network structure2016In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 6, article id 30790Article in journal (Refereed)
    Abstract [en]

    Large-scale transitions in societies are associated with both individual behavioural change and restructuring of the social network. These two factors have often been considered independently, yet recent advances in social network research challenge this view. Here we show that common features of societal marginalization and clustering emerge naturally during transitions in a co-evolutionary adaptive network model. This is achieved by explicitly considering the interplay between individual interaction and a dynamic network structure in behavioural selection. We exemplify this mechanism by simulating how smoking behaviour and the network structure get reconfigured by changing social norms. Our results are consistent with empirical findings: The prevalence of smoking was reduced, remaining smokers were preferentially connected among each other and formed increasingly marginalized clusters. We propose that self-amplifying feedbacks between individual behaviour and dynamic restructuring of the network are main drivers of the transition. This generative mechanism for co-evolution of individual behaviour and social network structure may apply to a wide range of examples beyond smoking.

  • 185. Scholl, Michael
    et al.
    Carter, Stephen F.
    Westman, Eric
    Rodriguez-Vieitez, Elena
    Almkvist, Ove
    Stockholm University, Faculty of Social Sciences, Department of Psychology. Karolinska Institutet, Sweden; Karolinska University Hospital, Sweden.
    Thordardottir, Steinunn
    Wall, Anders
    Graff, Caroline
    Långström, Bengt
    Nordberg, Agneta
    Early astrocytosis in autosomal dominant Alzheimer's disease measured in vivo by multi-tracer positron emission tomography2015In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 5, article id 16404Article in journal (Refereed)
    Abstract [en]

    Studying autosomal dominant Alzheimer's disease (ADAD), caused by gene mutations yielding nearly complete penetrance and a distinct age of symptom onset, allows investigation of presymptomatic pathological processes that can identify a therapeutic window for disease-modifying therapies. Astrocyte activation may occur in presymptomatic Alzheimer's disease (AD) because reactive astrocytes surround beta-amyloid (A beta) plaques in autopsy brain tissue. Positron emission tomography was performed to investigate fibrillar A beta, astrocytosis and cerebral glucose metabolism with the radiotracers C-11-Pittsburgh compound-B (PIB), C-11-deuterium-L-deprenyl (DED) and F-18-fluorodeoxyglucose (FDG) respectively in presymptomatic and symptomatic ADAD participants (n = 21), patients with mild cognitive impairment (n = 11) and sporadic AD (n = 7). Multivariate analysis using the combined data from all radiotracers clearly separated the different groups along the first and second principal components according to increased PIB retention/decreased FDG uptake (component 1) and increased DED binding (component 2). Presymptomatic ADAD mutation carriers showed significantly higher PIB retention than non-carriers in all brain regions except the hippocampus. DED binding was highest in presymptomatic ADAD mutation carriers. This suggests that non-fibrillar A beta or early stage plaque depostion might interact with inflammatory responses indicating astrocytosis as an early contributory driving force in AD pathology. The novelty of this finding will be investigated in longitudinal follow-up studies.

  • 186.
    Schäfer, Jacob
    et al.
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Dawitz, Hannah
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Ott, Martin
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Ädelroth, Pia
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Brzezinski, Peter
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Regulation of cytochrome c oxidase activity by modulation of the catalytic site2018In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, article id 11397Article in journal (Refereed)
    Abstract [en]

    The respiratory supercomplex factor 1 (Rcf 1) in Saccharomyces cerevisiae binds to intact cytochrome c oxidase (CytcO) and has also been suggested to be an assembly factor of the enzyme. Here, we isolated CytcO from rcf1Δ mitochondria using affinity chromatography and investigated reduction, inter-heme electron transfer and ligand binding to heme a3. The data show that removal of Rcf1 yields two CytcO sub-populations. One of these sub-populations exhibits the same functional behavior as CytcO isolated from the wild-type strain, which indicates that intact CytcO is assembled also without Rcf1. In the other sub-population, which was shown previously to display decreased activity and accelerated ligand-binding kinetics, the midpoint potential of the catalytic site was lowered. The lower midpoint potential allowed us to selectively reduce one of the two sub-populations of the rcf1Δ CytcO, which made it possible to investigate the functional behavior of the two CytcO forms separately. We speculate that these functional alterations reflect a mechanism that regulates O2 binding and trapping in CytcO, thereby altering energy conservation by the enzyme.

  • 187. Sinkko, Hanna
    et al.
    Hepolehto, Iina
    Lyra, Christina
    Rinta-Kanto, Johanna M.
    Villnäs, Anna
    Norkko, Joanna
    Norkko, Alf
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre. University of Helsinki, Finland.
    Imonen, Sari T.
    Increasing oxygen deficiency changes rare and moderately abundant bacterial communities in coastal soft sediments2019In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 9, article id 16341Article in journal (Refereed)
    Abstract [en]

    Coastal hypoxia is a major environmental problem worldwide. Hypoxia-induced changes in sediment bacterial communities harm marine ecosystems and alter biogeochemical cycles. Nevertheless, the resistance of sediment bacterial communities to hypoxic stress is unknown. We investigated changes in bacterial communities during hypoxic-anoxic disturbance by artificially inducing oxygen deficiency to the seafloor for 0, 3, 7, and 48 days, with subsequent molecular biological analyses. We further investigated relationships between bacterial communities, benthic macrofauna and nutrient effluxes across the sediment-water-interface during hypoxic-anoxic stress, considering differentially abundant operational taxonomic units (OTUs). The composition of the moderately abundant OTUs changed significantly after seven days of oxygen deficiency, while the abundant and rare OTUs first changed after 48 days. High bacterial diversity maintained the resistance of the communities during oxygen deficiency until it dropped after 48 days, likely due to anoxia-induced loss of macrofaunal diversity and bioturbation. Nutrient fluxes, especially ammonium, correlated positively with the moderate and rare OTUs, including potential sulfate reducers. Correlations may reflect bacteria-mediated nutrient effluxes that accelerate eutrophication. The study suggests that even slightly higher bottom-water oxygen concentrations, which could sustain macrofaunal bioturbation, enable bacterial communities to resist large compositional changes and decrease the harmful consequences of hypoxia in marine ecosystems.

  • 188.
    Sjöholm, Johannes
    et al.
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Bergstrand, Jan
    Nilsson, Tobias
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Šachl, Radek
    von Ballmoos, Christoph
    Widengren, Jerker
    Brzezinski, Peter
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    The lateral distance between a proton pump and ATP synthase determines the ATP-synthesis rate2017In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, article id 2926Article in journal (Refereed)
    Abstract [en]

    We have investigated the effect of lipid composition on interactions between cytochrome bo(3) and ATP-synthase, and the ATP-synthesis activity driven by proton pumping. The two proteins were labeled by fluorescent probes and co-reconstituted in large (d congruent to 100 nm) or giant (d congruent to 10 mu m) unilamellar lipid vesicles. Interactions were investigated using fluorescence correlation/cross-correlation spectroscopy and the activity was determined by measuring ATP production, driven by electron-proton transfer, as a function of time. We found that conditions that promoted direct interactions between the two proteins in the membrane (higher fraction DOPC lipids or labeling by hydrophobic molecules) correlated with an increased activity. These data indicate that the ATP-synthesis rate increases with decreasing distance between cytochrome bo3 and the ATP-synthase, and involves proton transfer along the membrane surface. The maximum distance for lateral proton transfer along the surface was found to be similar to 80 nm.

  • 189. Skedung, Lisa
    et al.
    Arvidsson, Martin
    Stockholm University, Faculty of Social Sciences, Department of Psychology.
    Chung, Jun Young
    Stafford, Christopher M.
    Berglund, Birgitta
    Stockholm University, Faculty of Social Sciences, Department of Psychology. Karolinska Institutet, Sweden.
    Rutland, Mark W.
    Feeling Small: Exploring the Tactile Perception Limits2013In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 3, p. 2617-Article in journal (Refereed)
    Abstract [en]

    The human finger is exquisitely sensitive in perceiving different materials, but the question remains as to what length scales are capable of being distinguished in active touch. We combine material science with psychophysics to manufacture and haptically explore a series of topographically patterned surfaces of controlled wavelength, but identical chemistry. Strain-induced surface wrinkling and subsequent templating produced 16 surfaces with wrinkle wavelengths ranging from 300 nm to 90 mu m and amplitudes between 7 nm and 4.5 mu m. Perceived similarities of these surfaces (and two blanks) were pairwise scaled by participants, and interdistances among all stimuli were determined by individual differences scaling (INDSCAL). The tactile space thus generated and its two perceptual dimensions were directly linked to surface physical properties - the finger friction coefficient and the wrinkle wavelength. Finally, the lowest amplitude of the wrinkles so distinguished was approximately 10 nm, demonstrating that human tactile discrimination extends to the nanoscale.

  • 190.
    Smirnova, Irina A.
    et al.
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Ädelroth, Pia
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Brzezinski, Peter
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Extraction and liposome reconstitution of membrane proteins with their native lipids without the use of detergents2018In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, article id 14950Article in journal (Refereed)
    Abstract [en]

    Functional studies of membrane-bound channels, transporters or signal transducers require that the protein of interest resides in a membrane that separates two compartments. One approach that is commonly used to prepare these systems is to reconstitute the protein in liposomes. An intermediate step of this method is purification of the protein, which typically involves solubilization of the native membrane using detergent. The use of detergents often results in removal of lipids surrounding the protein, which may alter its structure and function. Here, we have employed a method for isolation of membrane proteins with a disc of their native lipids to develop an approach that allows transfer of the purified membrane protein to liposomes without the use of any detergents.

  • 191. Sork, Helena
    et al.
    Corso, Giulia
    Krjutskov, Kaarel
    Johansson, Henrik J.
    Nordin, Joel Z.
    Wiklander, Oscar P. B.
    Lee, Yi Xin Fiona
    Orzechowski Westholm, Jakub
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics. Stockholm University, Science for Life Laboratory (SciLifeLab).
    Lehtiö, Janne
    Wood, Matthew J. A.
    Mäger, Imre
    El Andaloussi, Samir
    Heterogeneity and interplay of the extracellular vesicle small RNA transcriptome and proteome2018In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, article id 10813Article in journal (Refereed)
    Abstract [en]

    Extracellular vesicles (EVs) mediate cell-to-cell communication by delivering or displaying macromolecules to their recipient cells. While certain broad-spectrum EV effects reflect their protein cargo composition, others have been attributed to individual EV-loaded molecules such as specific miRNAs. In this work, we have investigated the contents of vesicular cargo using small RNA sequencing of cells and EVs from HEK293T, RD4, C2C12, Neuro2a and C17.2. The majority of RNA content in EVs (49-96%) corresponded to rRNA-, coding-and tRNA fragments, corroborating with our proteomic analysis of HEK293T and C2C12 EVs which showed an enrichment of ribosome and translation-related proteins. On the other hand, the overall proportion of vesicular small RNA was relatively low and variable (2-39%) and mostly comprised of miRNAs and sequences mapping to piRNA loci. Importantly, this is one of the few studies, which systematically links vesicular RNA and protein cargo of vesicles. Our data is particularly useful for future work in unravelling the biological mechanisms underlying vesicular RNA and protein sorting and serves as an important guide in developing EVs as carriers for RNA therapeutics.

  • 192. Stelbrink, Pablo
    et al.
    Pinkert, Stefan
    Brunzel, Stefan
    Kerr, Jeremy
    Wheat, Christopher W.
    Stockholm University, Faculty of Science, Department of Zoology.
    Brandl, Roland
    Zeuss, Dirk
    Stockholm University, Faculty of Science, Department of Zoology. Philipps-Universität Marburg, Germany.
    Colour lightness of butterfly assemblages across North America and Europe2019In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 9, article id 1760Article in journal (Refereed)
    Abstract [en]

    Melanin-based dark colouration is beneficial for insects as it increases the absorption of solar energy and protects against pathogens. Thus, it is expected that insect colouration is darker in colder regions and in regions with high humidity, where it is assumed that pathogen pressure is highest. These relationships between colour lightness, insect distribution, and climate between taxa and subtaxa across continents have never been tested and compared. Here we analysed the colour lightness of nearly all butterfly species of North America and Europe using the average colour lightness of species occurring within 50 km x 50 km grid cells across both continents as the dependent variable and average insolation, temperature and humidity within grid cells as explanatory variables. We compared the direction, strength and shape of these relationships between butterfly families and continents. On both continents, butterfly assemblages in colder and more humid regions were generally darker coloured than assemblages in warmer and less humid regions. Although these relationships differed in detail between families, overall trends within families on both continents were similar. Our results add further support for the importance of insect colour lightness as a mechanistic adaptation to climate that influences biogeographical patterns of species distributions.

  • 193.
    Stranne, Christian
    et al.
    Stockholm University, Faculty of Science, Department of Geological Sciences. University of New Hampshire, USA.
    Mayer, Larry
    Weber, Thomas C.
    Ruddick, Barry R.
    Jakobsson, Martin
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Jerram, Kevin
    Weidner, Elizabeth
    Nilsson, Johan
    Stockholm University, Faculty of Science, Department of Meteorology .
    Gårdfeldt, Katarina
    Acoustic Mapping of Thermohaline Staircases in the Arctic Ocean2017In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, article id 15192Article in journal (Refereed)
    Abstract [en]

    Although there is enough heat contained in inflowing warm Atlantic Ocean water to melt all Arctic sea ice within a few years, a cold halocline limits upward heat transport from the Atlantic water. The amount of heat that penetrates the halocline to reach the sea ice is not well known, but vertical heat transport through the halocline layer can significantly increase in the presence of double diffusive convection. Such convection can occur when salinity and temperature gradients share the same sign, often resulting in the formation of thermohaline staircases. Staircase structures in the Arctic Ocean have been previously identified and the associated double diffusive convection has been suggested to influence the Arctic Ocean in general and the fate of the Arctic sea ice cover in particular. A central challenge to understanding the role of double diffusive convection in vertical heat transport is one of observation. Here, we use broadband echo sounders to characterize Arctic thermohaline staircases at their full vertical and horizontal resolution over large spatial areas (100 s of kms). In doing so, we offer new insight into the mechanism of thermohaline staircase evolution and scale, and hence fluxes, with implications for understanding ocean mixing processes and ocean-sea ice interactions.

  • 194. Sumida, K.
    et al.
    Ishida, Y.
    Zhu, S.
    Ye, M.
    Pertsova, Anna
    Stockholm University, Nordic Institute for Theoretical Physics (Nordita). Center for Quantum Materials (CQM), Sweden.
    Triola, Christopher
    Stockholm University, Nordic Institute for Theoretical Physics (Nordita). Center for Quantum Materials (CQM), Sweden.
    Kokh, K. A.
    Tereshchenko, O. E.
    Balatsky, Alexander V.
    Stockholm University, Nordic Institute for Theoretical Physics (Nordita). Center for Quantum Materials (CQM), Sweden; Los Alamos National Laboratory, USA; ETH Institute for Theoretical Studies, Switzerland; University of Connecticut, USA.
    Shin, S.
    Kimura, A.
    Prolonged duration of nonequilibrated Dirac fermions in neutral topological insulators2017In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, article id 14080Article in journal (Refereed)
    Abstract [en]

    Topological insulators (TIs) possess spin-polarized Dirac fermions on their surface but their unique properties are often masked by residual carriers in the bulk. Recently, (Sb1-xBix)(2)Te-3 was introduced as a non-metallic TI whose carrier type can be tuned from n to p across the charge neutrality point. By using time-and angle-resolved photoemission spectroscopy, we investigate the ultrafast carrier dynamics in the series of (Sb1-xBix)(2)Te-3. The Dirac electronic recovery of similar to 10 ps at most in the bulk-metallic regime elongated to >400 ps when the charge neutrality point was approached. The prolonged nonequilibration is attributed to the closeness of the Fermi level to the Dirac point and to the high insulation of the bulk. We also discuss the feasibility of observing excitonic instability of (Sb1-xBix)(2)Te-3.

  • 195.
    Sundelin, Tina
    et al.
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet, Sweden; New York University, USA.
    Bayard, Frida
    Schwarz, Johanna
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet, Sweden.
    Cybulski, Lukasz
    Petrovic, Predrag
    Axelsson, John
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet, Sweden.
    Framing effect, probability distortion, and gambling tendency without feedback are resistant to two nights of experimental sleep restriction2019In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 9, article id 8554Article in journal (Refereed)
    Abstract [en]

    Several studies suggest that sleep deprivation affects risky decision making. However, most of these are confounded by feedback given after each decision, indicating that decisions may be based on suboptimal feedback-learning rather than risk evaluation. Furthermore, few studies have investigated the effect of sleep loss on aspects of prospect theory, specifically the framing effect and probability distortion. In this within-subjects design, 25 people had (i) two nights of an 8 h sleep opportunity, and (ii) two nights of a 4 h sleep opportunity, in a counter-balanced order. Following the two nights, they performed a gambling task with no immediate feedback; for each round, they could either gamble for a full amount, or take a settlement framed as a gain or a loss for part of the amount. Sleep restriction did not significantly affect the tendency to gamble, the framing effect, or probability distortion, as compared to normal sleep. These results indicate that two nights of sleep restriction affects neither general gambling tendency, nor two of the main predictions of prospect theory. This resilience may be due to a less extreme sleep loss than in previous studies, but also indicates that learning components and risk biases should be separated when assessing the effect of sleep loss on risky behaviour.

  • 196.
    Sundqvist, Hanna S.
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Holmgren, Karin
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Fohlmeister, J.
    Zhang, Qiong
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Bar Matthews, M.
    Spötl, C.
    Körnich, H.
    Evidence of a large cooling between 1690 and 1740 AD in southern Africa2013In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 3, article id 1767Article in journal (Refereed)
    Abstract [en]

    A 350-year-long, well-dated delta O-18 stalagmite record from the summer rainfall region in South Africa is positively correlated with regional air surface temperatures at interannual time scales. The coldest period documented in this record occurred between 1690 and 1740, slightly lagging the Maunder Minimum (1645-1710). A temperature reconstruction, based on the correlation between regional surface temperatures and the stalagmite delta O-18 variations, indicates that parts of this period could have been as much as 1.4 degrees C colder than today. Significant cycles of 22, 11 and 4.8 years demonstrate that the solar magnetic and the El Nino-Southern Oscillation cycle could be important drivers of multidecadal to interannual climate variability in this region. The observation that the most important driver of stalagmite delta O-18 on interannual time scales from this subtropical region is regional surface temperature cautions against deterministic interpretations of delta O-18 variations in low-latitude stalagmites as mainly driven by the amount of precipitation.

  • 197. Säterberg, Torbjörn
    et al.
    Jonsson, Tomas
    Yearsley, Jon
    Berg, Sofia
    Ebenman, Bo
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. Linköping University, Sweden.
    A potential role for rare species in ecosystem dynamics2019In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 9, article id 11107Article in journal (Refereed)
    Abstract [en]

    The ecological importance of common species for many ecosystem processes and functions is unquestionably due to their high a bundance. Yet, the importance of rare species is much less understood. Here we take a theoretical approach, exposing dynamical models of ecological networks to small perturbations, to explore the dynamical importance of rare and common species. We find that both species types contribute to the recovery of communities following generic perturbations (i.e. perturbations affecting all species). Yet, when perturbations are selective (i.e. affects only one species), perturbations to rare species have the most pronounced effect on community stability. We show that this is due to the strong indirect effects induced by perturbations to rare species. Because indirect effects typically set in at longer timescales, our results indicate that the importance of rare species may be easily overlooked and thus underrated. Hence, our study provides a potential ecological motive for the management and protection of rare species.

  • 198. Tabor, J.
    et al.
    Griep, Yannick
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. University of Calgary, Canada.
    Collins, R.
    Mychasiuk, R.
    Investigating the Neurological Correlates of Workplace Deviance Using a Rodent Model of Extinction2018In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, article id 17316Article in journal (Refereed)
    Abstract [en]

    Employee deviance and time theft is an expensive and pervasive workplace problem. Research indicates that a primary reason employees engage in deviant behaviour is the perception of injustice often associated with psychological contract breach (i.e., broken promises). This study used a rodent model to mimic said experience of broken promises and then examined the subsequent neurophysiological changes that lead to the display of deviant behaviours. Specifically, we generated a psychological contract using a 3 choice serial reaction task, then broke the promise, and finally examined deviant behaviours and neurological correlates. After the broken promise, rats had elevated levels of corticosterone and testosterone, engaged in riskier behaviour, and were more aggressive. The most prominent changes in gene expression were associated with serotonin and stress, and were found in the nucleus accumbens. This study highlights the value of pre-clinical models in the investigation of the theoretical tenants of industrial and organizational psychology.

  • 199.
    Tamm, Sandra
    et al.
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet, Sweden.
    Nilssone, Gustav
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet, Sweden.
    Schwarz, Johanna
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet, Sweden.
    Lamm, Claus
    Kecklund, Göran
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Radboud Universiteit, Netherlands.
    Petrovic, Predrag
    Fischer, Håkan
    Stockholm University, Faculty of Social Sciences, Department of Psychology, Biological psychology.
    Åkerstedt, Torbjörn
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet, Sweden.
    Lekander, Mats
    Stockholm University, Faculty of Social Sciences, Stress Research Institute. Karolinska Institutet, Sweden.
    The effect of sleep restriction on empathy for pain: An fMRI study in younger and older adults2017In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, article id 12236Article in journal (Refereed)
    Abstract [en]

    Age and sleep both affect emotional functioning. Since sleep patterns change over the lifespan, we investigated the effects of short sleep and age on empathic responses. In a randomized cross-over experimental design, healthy young and older volunteers (n = 47 aged 20–30 years and n = 39 aged 65–75 years) underwent functional magnetic resonance imaging (fMRI) after normal sleep or night sleep restricted to 3 hours. During fMRI, participants viewed pictures of needles pricking a hand (pain) or Q-tips touching a hand (control), a well-established paradigm to investigate empathy for pain. There was no main effect of sleep restriction on empathy. However, age and sleep interacted so that sleep restriction caused increased unpleasantness in older but not in young participants. Irrespective of sleep condition, older participants showed increased activity in angular gyrus, superior temporal sulcus and temporo-parietal junction compared to young. Speculatively, this could indicate that the older individuals adopted a more cognitive approach in response to others’ pain. Our findings suggest that caution in generalizability across age groups is needed in further studies of sleep on social cognition and emotion.

  • 200.
    Tavakoli, Armin
    et al.
    Stockholm University, Faculty of Science, Department of Physics.
    Cabello, Adan
    Zukowski, Marek
    Bourennane, Mohamed
    Stockholm University, Faculty of Science, Department of Physics.
    Quantum Clock Synchronization with a Single Qudit2015In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 5, article id 7982Article in journal (Refereed)
    Abstract [en]

    Clock synchronization for nonfaulty processes in multiprocess networks is indispensable for a variety of technologies. A reliable system must be able to resynchronize the nonfaulty processes upon some components failing causing the distribution of incorrect or conflicting information in the network. The task of synchronizing such networks is related to Byzantine agreement (BA), which can classically be solved using recursive algorithms if and only if less than one-third of the processes are faulty. Here we introduce a nonrecursive quantum algorithm, based on a quantum solution of the detectable BA, which achieves clock synchronization in the presence of arbitrary many faulty processes by using only a single quantum system.

12345 151 - 200 of 229
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf