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Sökning: WFRF:(Nikolov P.)

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  • de Jong, S, et al. (författare)
  • Applying polygenic risk scoring for psychiatric disorders to a large family with bipolar disorder and major depressive disorder
  • 2018
  • Ingår i: Communications biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 1, s. 163-
  • Tidskriftsartikel (refereegranskat)abstract
    • Psychiatric disorders are thought to have a complex genetic pathology consisting of interplay of common and rare variation. Traditionally, pedigrees are used to shed light on the latter only, while here we discuss the application of polygenic risk scores to also highlight patterns of common genetic risk. We analyze polygenic risk scores for psychiatric disorders in a large pedigree (n ~ 260) in which 30% of family members suffer from major depressive disorder or bipolar disorder. Studying patterns of assortative mating and anticipation, it appears increased polygenic risk is contributed by affected individuals who married into the family, resulting in an increasing genetic risk over generations. This may explain the observation of anticipation in mood disorders, whereby onset is earlier and the severity increases over the generations of a family. Joint analyses of rare and common variation may be a powerful way to understand the familial genetics of psychiatric disorders.
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  • Snodgrass, C., et al. (författare)
  • The 67P/Churyumov-Gerasimenko observation campaign in support of the Rosetta mission
  • 2017
  • Ingår i: Philosophical Transactions. Series A. - : The Royal Society. - 1364-503X .- 1471-2962. ; 375:2097
  • Tidskriftsartikel (refereegranskat)abstract
    • We present a summary of the campaign of remote observations that supported the European Space Agency's Rosetta mission. Telescopes across the globe (and in space) followed comet 67P/ Churyumov-Gerasimenko from before Rosetta's arrival until nearly the end of the mission in September 2016. These provided essential data for mission planning, large-scale context information for the coma and tails beyond the spacecraft and a way to directly compare 67P with other comets. The observations revealed 67P to be a relatively 'well-behaved' comet, typical of Jupiter family comets and with activity patterns that repeat from orbit to orbit. Comparison between this large collection of telescopic observations and the in situ results from Rosetta will allow us to better understand comet coma chemistry and structure. This work is just beginning as the mission ends-in this paper, we present a summary of the ground-based observations and early results, and point to many questions that will be addressed in future studies. This article is part of the themed issue 'Cometary science after Rosetta'.
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  • Allaria, E., et al. (författare)
  • Highly coherent and stable pulses from the FERMI seeded free-electron laser in the extreme ultraviolet
  • 2012
  • Ingår i: Nature Photonics. - 1749-4885. ; 6:10, s. 699-704
  • Tidskriftsartikel (refereegranskat)abstract
    • Free-electron lasers (FELs) are promising devices for generating light with laser-like properties in the extreme ultraviolet and X-ray spectral regions. Recently, FELs based on the self-amplified spontaneous emission (SASE) mechanism have allowed major breakthroughs in diffraction and spectroscopy applications, despite the relatively large shot-to-shot intensity and photon-energy fluctuations and the limited longitudinal coherence inherent in the SASE mechanism. Here, we report results on the initial performance of the FERMI seeded FEL, based on the high-gain harmonic generation configuration, in which an external laser is used to initiate the emission process. Emission from the FERMI FEL-1 source occurs in the form of pulses carrying energy of several tens of microjoules per pulse and tunable throughout the 65 to 20 nm wavelength range, with unprecedented shot-to-shot wavelength stability, low-intensity fluctuations, close to transform-limited bandwidth, transverse and longitudinal coherence and full control of polarization.
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  • Finetti, P., et al. (författare)
  • Pulse duration of seeded free electron lasers
  • 2017
  • Ingår i: Physical Review X. - 2160-3308. ; 7:2
  • Tidskriftsartikel (refereegranskat)abstract
    • The pulse duration, and, more generally, the temporal intensity profile of free-electron laser (FEL) pulses, is of utmost importance for exploring the new perspectives offered by FELs; it is a nontrivial experimental parameter that needs to be characterized. We measured the pulse shape of an extreme ultraviolet externally seeded FEL operating in high-gain harmonic generation mode. Two different methods based on the cross-correlation of the FEL pulses with an external optical laser were used. The two methods, one capable of single-shot performance, may both be implemented as online diagnostics in FEL facilities. The measurements were carried out at the seeded FEL facility FERMI. The FEL temporal pulse characteristics were measured and studied in a range of FEL wavelengths and machine settings, and they were compared to the predictions of a theoretical model. The measurements allowed a direct observation of the pulse lengthening and splitting at saturation, in agreement with the proposed theory.
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  • Iablonskyi, D., et al. (författare)
  • Slow Interatomic Coulombic Decay of Multiply Excited Neon Clusters
  • 2016
  • Ingår i: Physical Review Letters. - 0031-9007. ; 117:27
  • Tidskriftsartikel (refereegranskat)abstract
    • Ne clusters (∼5000 atoms) were resonantly excited (2p→3s) by intense free electron laser (FEL) radiation at FERMI. Such multiply excited clusters can decay nonradiatively via energy exchange between at least two neighboring excited atoms. Benefiting from the precise tunability and narrow bandwidth of seeded FEL radiation, specific sites of the Ne clusters were probed. We found that the relaxation of cluster surface atoms proceeds via a sequence of interatomic or intermolecular Coulombic decay (ICD) processes while ICD of bulk atoms is additionally affected by the surrounding excited medium via inelastic electron scattering. For both cases, cluster excitations relax to atomic states prior to ICD, showing that this kind of ICD is rather slow (picosecond range). Controlling the average number of excitations per cluster via the FEL intensity allows a coarse tuning of the ICD rate.
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  • Kehoe, Laura, et al. (författare)
  • Make EU trade with Brazil sustainable
  • 2019
  • Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 364:6438, s. 341-
  • Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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  • Bell, Taylor, et al. (författare)
  • Nightside clouds and disequilibrium chemistry on the hot Jupiter WASP-43b
  • 2024
  • Ingår i: Nature Astronomy. - 2397-3366. ; In Press
  • Tidskriftsartikel (refereegranskat)abstract
    • Hot Jupiters are among the best-studied exoplanets, but it is still poorly understood how their chemical composition and cloud properties vary with longitude. Theoretical models predict that clouds may condense on the nightside and that molecular abundances can be driven out of equilibrium by zonal winds. Here we report a phase-resolved emission spectrum of the hot Jupiter WASP-43b measured from 5 μm to 12 μm with the JWST’s Mid-Infrared Instrument. The spectra reveal a large day–night temperature contrast (with average brightness temperatures of 1,524 ± 35 K and 863 ± 23 K, respectively) and evidence for water absorption at all orbital phases. Comparisons with three-dimensional atmospheric models show that both the phase-curve shape and emission spectra strongly suggest the presence of nightside clouds that become optically thick to thermal emission at pressures greater than ~100 mbar. The dayside is consistent with a cloudless atmosphere above the mid-infrared photosphere. Contrary to expectations from equilibrium chemistry but consistent with disequilibrium kinetics models, methane is not detected on the nightside (2σ upper limit of 1–6 ppm, depending on model assumptions). Our results provide strong evidence that the atmosphere of WASP-43b is shaped by disequilibrium processes and provide new insights into the properties of the planet’s nightside clouds. However, the remaining discrepancies between our observations and our predictive atmospheric models emphasize the importance of further exploring the effects of clouds and disequilibrium chemistry in numerical models.
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  • Rangelow, I. W., et al. (författare)
  • Piezoresistive and self-actuated 128-cantilever arrays for nanotechnology applications
  • 2007
  • Ingår i: Microelectronic Engineering. - : Elsevier BV. - 0167-9317 .- 1873-5568. ; 84:5-8, s. 1260-1264
  • Tidskriftsartikel (refereegranskat)abstract
    • A major limitation for future nanotechnology, particularly for bottom-up manufacturing is the non-availability of 2-dimensional massively parallel probe arrays. Scanning proximity probes are uniquely powerful tools for analysis, manipulation and bottom-up synthesis: they are capable of addressing and engineering surfaces at the atomic level and are the key to unlocking the full potential of Nanotechnology. Generic massively parallel intelligent cantilever-probe platforms is demonstrated through a number of existing and ground-breaking techniques. A packaged VLSI NEMS-chip (Very Large Scale Integrated Nano Electro Mechanical System) incorporating 128 proximal probes, fully addressable with control and readout interconnects and advanced software will be presented.
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  • Christova, P, et al. (författare)
  • Fluorescence studies on denaturation and stability of recombinant human interferon-gamma
  • 2003
  • Ingår i: Zeitschrift fur Naturforschung. C, Journal of biosciences. - : Walter de Gruyter GmbH. - 0939-5075. ; 58:3-4, s. 288-294
  • Tidskriftsartikel (refereegranskat)abstract
    • Unfolding/folding transitions of recombinant human interferon-gamma (hIFNγ) in urea and guanidine chloride (Gn.HCl) solutions were studied by fluorescence spectroscopy. At pH 7.4 Gn.HCl was a much more efficient denaturant (midpoint of unfolding C* = 1.1 m and ΔG0 = 13.4 kJ/mol) than urea (C* = 2.8 m and ΔG0 = 11.7 kJ/mol). The close ΔG0 values indicate that the contribution of electrostatic interactions to the stability of hIFNγ is insignificant. Both the pH dependence of the fluorescence intensity and the unfolding experiments in urea at variable pH showed that hIFNγ remains native in the pH range of 4.8-9.5. Using two quenchers, iodide and acrylamide, and applying the Stern-Volmer equation, a cluster of acidic groups situated in close proximity to the single tryptophan residue was identified. Based on the denaturation experiments at different pH values and on our earlier calculations of the electrostatic interactions in hIFNγ, we assume that the protonation of Asp63 causes conformational changes having a substantial impact on the stability of hIFNγ.
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  • Forzieri, Giovanni, et al. (författare)
  • The Database of European Forest Insect and Disease Disturbances: DEFID2
  • 2023
  • Ingår i: Global Change Biology. - 1365-2486. ; 29:21, s. 6040-6065
  • Tidskriftsartikel (refereegranskat)abstract
    • Insect and disease outbreaks in forests are biotic disturbances that can profoundly alter ecosystem dynamics. In many parts of the world, these disturbance regimes are intensifying as the climate changes and shifts the distribution of species and biomes. As a result, key forest ecosystem services, such as carbon sequestration, regulation of water flows, wood production, protection of soils, and the conservation of biodiversity, could be increasingly compromised. Despite the relevance of these detrimental effects, there are currently no spatially detailed databases that record insect and disease disturbances on forests at the pan-European scale. Here, we present the new Database of European Forest Insect and Disease Disturbances (DEFID2). It comprises over 650,000 harmonized georeferenced records, mapped as polygons or points, of insects and disease disturbances that occurred between 1963 and 2021 in European forests. The records currently span eight different countries and were acquired through diverse methods (e.g., ground surveys, remote sensing techniques). The records in DEFID2 are described by a set of qualitative attributes, including severity and patterns of damage symptoms, agents, host tree species, climate-driven trigger factors, silvicultural practices, and eventual sanitary interventions. They are further complemented with a satellite-based quantitative characterization of the affected forest areas based on Landsat Normalized Burn Ratio time series, and damage metrics derived from them using the LandTrendr spectral–temporal segmentation algorithm (including onset, duration, magnitude, and rate of the disturbance), and possible interactions with windthrow and wildfire events. The DEFID2 database is a novel resource for many large-scale applications dealing with biotic disturbances. It offers a unique contribution to design networks of experiments, improve our understanding of ecological processes underlying biotic forest disturbances, monitor their dynamics, and enhance their representation in land-climate models. Further data sharing is encouraged to extend and improve the DEFID2 database continuously. The database is freely available at https://jeodpp.jrc.ec.europa.eu/ftp/jrc-opendata/FOREST/DISTURBANCES/DEFID2/.
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  • Gauld, Jethro G., et al. (författare)
  • Hotspots in the grid : Avian sensitivity and vulnerability to collision risk from energy infrastructure interactions in Europe and North Africa
  • 2022
  • Ingår i: Journal of Applied Ecology. - : John Wiley & Sons. - 0021-8901 .- 1365-2664. ; 59:6, s. 1496-1512
  • Tidskriftsartikel (refereegranskat)abstract
    • Wind turbines and power lines can cause bird mortality due to collision or electrocution. The biodiversity impacts of energy infrastructure (EI) can be minimised through effective landscape-scale planning and mitigation. The identification of high-vulnerability areas is urgently needed to assess potential cumulative impacts of EI while supporting the transition to zero carbon energy. We collected GPS location data from 1,454 birds from 27 species susceptible to collision within Europe and North Africa and identified areas where tracked birds are most at risk of colliding with existing EI. Sensitivity to EI development was estimated for wind turbines and power lines by calculating the proportion of GPS flight locations at heights where birds were at risk of collision and accounting for species' specific susceptibility to collision. We mapped the maximum collision sensitivity value obtained across all species, in each 5 x 5 km grid cell, across Europe and North Africa. Vulnerability to collision was obtained by overlaying the sensitivity surfaces with density of wind turbines and transmission power lines. Results: Exposure to risk varied across the 27 species, with some species flying consistently at heights where they risk collision. For areas with sufficient tracking data within Europe and North Africa, 13.6% of the area was classified as high sensitivity to wind turbines and 9.4% was classified as high sensitivity to transmission power lines. Sensitive areas were concentrated within important migratory corridors and along coastlines. Hotspots of vulnerability to collision with wind turbines and transmission power lines (2018 data) were scattered across the study region with highest concentrations occurring in central Europe, near the strait of Gibraltar and the Bosporus in Turkey. Synthesis and applications. We identify the areas of Europe and North Africa that are most sensitive for the specific populations of birds for which sufficient GPS tracking data at high spatial resolution were available. We also map vulnerability hotspots where mitigation at existing EI should be prioritised to reduce collision risks. As tracking data availability improves our method could be applied to more species and areas to help reduce bird-EI conflicts.
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  • Hendriks, Kasper P., et al. (författare)
  • Global Brassicaceae phylogeny based on filtering of 1,000-gene dataset
  • 2023
  • Ingår i: Current Biology. - : Elsevier. - 0960-9822 .- 1879-0445. ; 33:19, s. 4052-4068
  • Tidskriftsartikel (refereegranskat)abstract
    • The mustard family (Brassicaceae) is a scientifically and economically important family, containing the model plant Arabidopsis thaliana and numerous crop species that feed billions worldwide. Despite its relevance, most phylogenetic trees of the family are incompletely sampled and often contain poorly supported branches. Here, we present the most complete Brassicaceae genus-level family phylogenies to date (Bras-sicaceae Tree of Life or BrassiToL) based on nuclear (1,081 genes, 319 of the 349 genera; 57 of the 58 tribes) and plastome (60 genes, 265 genera; all tribes) data. We found cytonuclear discordance between the two, which is likely a result of rampant hybridization among closely and more distantly related lineages. To eval-uate the impact of such hybridization on the nuclear phylogeny reconstruction, we performed five different gene sampling routines, which increasingly removed putatively paralog genes. Our cleaned subset of 297 genes revealed high support for the tribes, whereas support for the main lineages (supertribes) was moder-ate. Calibration based on the 20 most clock-like nuclear genes suggests a late Eocene to late Oligocene origin of the family. Finally, our results strongly support a recently published new family classification, dividing the family into two subfamilies (one with five supertribes), together representing 58 tribes. This includes five recently described or re-established tribes, including Arabidopsideae, a monogeneric tribe accommodating Arabidopsis without any close relatives. With a worldwide community of thousands of researchers working on Brassicaceae and its diverse members, our new genus-level family phylogeny will be an indispensable tool for studies on biodiversity and plant biology.
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  • Hennecke, Martin, et al. (författare)
  • Ultrafast opto-magnetic effects in the extreme ultraviolet spectral range
  • 2024
  • Ingår i: Communications Physics. - : Springer Nature. - 2399-3650. ; 7:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Coherent light-matter interactions mediated by opto-magnetic phenomena like the inverse Faraday effect (IFE) are expected to provide a non-thermal pathway for ultrafast manipulation of magnetism on timescales as short as the excitation pulse itself. As the IFE scales with the spin-orbit coupling strength of the involved electronic states, photo-exciting the strongly spin-orbit coupled core-level electrons in magnetic materials appears as an appealing method to transiently generate large opto-magnetic moments. Here, we investigate this scenario in a ferrimagnetic GdFeCo alloy by using intense and circularly polarized pulses of extreme ultraviolet radiation. Our results reveal ultrafast and strong helicity-dependent magnetic effects which are in line with the characteristic fingerprints of an IFE, corroborated by ab initio opto-magnetic IFE theory and atomistic spin dynamics simulations.
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  • Kortenkamp, Andreas, et al. (författare)
  • Removing Critical Gaps in Chemical Test Methods by Developing New Assays for the Identification of Thyroid Hormone System-Disrupting Chemicals-The ATHENA Project
  • 2020
  • Ingår i: International Journal of Molecular Sciences. - : MDPI. - 1661-6596 .- 1422-0067. ; 21:9
  • Tidskriftsartikel (refereegranskat)abstract
    • The test methods that currently exist for the identification of thyroid hormone system-disrupting chemicals are woefully inadequate. There are currently no internationally validated in vitro assays, and test methods that can capture the consequences of diminished or enhanced thyroid hormone action on the developing brain are missing entirely. These gaps put the public at risk and risk assessors in a difficult position. Decisions about the status of chemicals as thyroid hormone system disruptors currently are based on inadequate toxicity data. The ATHENA project (Assays for the identification of Thyroid Hormone axis-disrupting chemicals: Elaborating Novel Assessment strategies) has been conceived to address these gaps. The project will develop new test methods for the disruption of thyroid hormone transport across biological barriers such as the blood-brain and blood-placenta barriers. It will also devise methods for the disruption of the downstream effects on the brain. ATHENA will deliver a testing strategy based on those elements of the thyroid hormone system that, when disrupted, could have the greatest impact on diminished or enhanced thyroid hormone action and therefore should be targeted through effective testing. To further enhance the impact of the ATHENA test method developments, the project will develop concepts for better international collaboration and development in the area of thyroid hormone system disruptor identification and regulation.
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  • Pilotto, Francesca, et al. (författare)
  • Meta-analysis of multidecadal biodiversity trends in Europe
  • 2020
  • Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 11:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Local biodiversity trends over time are likely to be decoupled from global trends, as local processes may compensate or counteract global change. We analyze 161 long-term biological time series (15-91 years) collected across Europe, using a comprehensive dataset comprising ~6,200 marine, freshwater and terrestrial taxa. We test whether (i) local long-term biodiversity trends are consistent among biogeoregions, realms and taxonomic groups, and (ii) changes in biodiversity correlate with regional climate and local conditions. Our results reveal that local trends of abundance, richness and diversity differ among biogeoregions, realms and taxonomic groups, demonstrating that biodiversity changes at local scale are often complex and cannot be easily generalized. However, we find increases in richness and abundance with increasing temperature and naturalness as well as a clear spatial pattern in changes in community composition (i.e. temporal taxonomic turnover) in most biogeoregions of Northern and Eastern Europe. The global biodiversity decline might conceal complex local and group-specific trends. Here the authors report a quantitative synthesis of longterm biodiversity trends across Europe, showing how, despite overall increase in biodiversity metric and stability in abundance, trends differ between regions, ecosystem types, and taxa.
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