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Sökning: WFRF:(Johannesson U)

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  • Clark, DW, et al. (författare)
  • Associations of autozygosity with a broad range of human phenotypes
  • 2019
  • Ingår i: Nature communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 10:1, s. 4957-
  • Tidskriftsartikel (refereegranskat)abstract
    • In many species, the offspring of related parents suffer reduced reproductive success, a phenomenon known as inbreeding depression. In humans, the importance of this effect has remained unclear, partly because reproduction between close relatives is both rare and frequently associated with confounding social factors. Here, using genomic inbreeding coefficients (FROH) for >1.4 million individuals, we show that FROH is significantly associated (p < 0.0005) with apparently deleterious changes in 32 out of 100 traits analysed. These changes are associated with runs of homozygosity (ROH), but not with common variant homozygosity, suggesting that genetic variants associated with inbreeding depression are predominantly rare. The effect on fertility is striking: FROH equivalent to the offspring of first cousins is associated with a 55% decrease [95% CI 44–66%] in the odds of having children. Finally, the effects of FROH are confirmed within full-sibling pairs, where the variation in FROH is independent of all environmental confounding.
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  • Abeysekara, A. U., et al. (författare)
  • VERITAS and Fermi-LAT Observations of TeV Gamma-Ray Sources Discovered by HAWC in the 2HWC Catalog
  • 2018
  • Ingår i: Astrophysical Journal. - : Institute of Physics Publishing. - 0004-637X .- 1538-4357. ; 866:1
  • Tidskriftsartikel (refereegranskat)abstract
    • The High Altitude Water Cherenkov (HAWC) collaboration recently published their 2HWC catalog, listing 39 very high energy (VHE; >100 GeV) gamma-ray sources based on 507 days of observation. Among these, 19 sources are not associated with previously known teraelectronvolt (TeV) gamma-ray sources. We have studied 14 of these sources without known counterparts with VERITAS and Fermi-LAT. VERITAS detected weak gamma-ray emission in the 1 TeV-30 TeV band in the region of DA 495, a pulsar wind nebula coinciding with 2HWC J1953+294, confirming the discovery of the source by HAWC. We did not find any counterpart for the selected 14 new HAWC sources from our analysis of Fermi-LAT data for energies higher than 10 GeV. During the search, we detected gigaelectronvolt (GeV) gamma-ray emission coincident with a known TeV pulsar wind nebula, SNR G54.1+0.3 (VER J1930+188), and a 2HWC source, 2HWC J1930+188. The fluxes for isolated, steady sources in the 2HWC catalog are generally in good agreement with those measured by imaging atmospheric Cherenkov telescopes. However, the VERITAS fluxes for SNR G54.1+0.3, DA 495, and TeV J2032+4130 are lower than those measured by HAWC, and several new HAWC sources are not detected by VERITAS. This is likely due to a change in spectral shape, source extension, or the influence of diffuse emission in the source region.
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  • Abramowski, A., et al. (författare)
  • Simultaneous multi-wavelength campaign on PKS 2005-489 in a high state
  • 2011
  • Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 533, s. A110-
  • Tidskriftsartikel (refereegranskat)abstract
    • The high-frequency peaked BL Lac object PKS 2005-489 was the target of a multi-wavelength campaign with simultaneous observations in the TeV gamma-ray (H.E.S.S.), GeV gamma-ray (Fermi/LAT), X-ray (RXTE, Swift), UV (Swift) and optical (ATOM, Swift) bands. This campaign was carried out during a high flux state in the synchrotron regime. The flux in the optical and X-ray bands reached the level of the historical maxima. The hard GeV spectrum observed with Fermi/LAT connects well to the very high energy (VHE, E > 100 GeV) spectrum measured with H.E.S.S. with a peak energy between similar to 5 and 500 GeV. Compared to observations with contemporaneous coverage in the VHE and X-ray bands in 2004, the X-ray flux was similar to 50 times higher during the 2009 campaign while the TeV gamma-ray flux shows marginal variation over the years. The spectral energy distribution during this multi-wavelength campaign was fit by a one zone synchrotron self-Compton model with a well determined cutoff in X-rays. The parameters of a one zone SSC model are inconsistent with variability time scales. The variability behaviour over years with the large changes in synchrotron emission and small changes in the inverse Compton emission does not warrant an interpretation within a one-zone SSC model despite an apparently satisfying fit to the broadband data in 2009.
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  • Aharonian, F., et al. (författare)
  • SIMULTANEOUS OBSERVATIONS OF PKS 2155-304 WITH HESS, FERMI, RXTE, AND ATOM : SPECTRAL ENERGY DISTRIBUTIONS AND VARIABILITY IN A LOW STATE
  • 2009
  • Ingår i: Astrophysical Journal Letters. - 2041-8205 .- 0004-637X .- 1538-4357. ; 696:2, s. L150-L155
  • Tidskriftsartikel (refereegranskat)abstract
    • We report on the first simultaneous observations that cover the optical, X-ray, and high-energy gamma-ray bands of the BL Lac object PKS 2155-304. The gamma-ray bands were observed for 11 days, between 2008 August 25 and 2008 September 6 (MJD 54704-54715), jointly with the Fermi Gamma-ray Space Telescope and the HESS atmospheric Cherenkov array, providing the first simultaneous MeV-TeV spectral energy distribution (SED) with the new generation of gamma-ray telescopes. The ATOM telescope and the RXTE and Swift observatories provided optical and X-ray coverage of the low-energy component over the same time period. The object was close to the lowest archival X-ray and very high energy (VHE; > 100 GeV) state, whereas the optical flux was much higher. The light curves show relatively little (similar to 30%) variability overall when compared to past flaring episodes, but we find a clear optical/VHE correlation and evidence for a correlation of the X-rays with the high-energy spectral index. Contrary to previous observations in the flaring state, we do not find any correlation between the X-ray and VHE components. Although synchrotron self-Compton models are often invoked to explain the SEDs of BL Lac objects, the most common versions of these models are at odds with the correlated variability we find in the various bands for PKS 2155-304.
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  • Abdalla, H., et al. (författare)
  • Gamma-ray blazar spectra with HESS II mono analysis : The case of PKS2155-304 and PG1553+113
  • 2017
  • Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 600
  • Tidskriftsartikel (refereegranskat)abstract
    • Context. The addition of a 28 m Cherenkov telescope (CT5) to the H.E.S.S. array extended the experiment's sensitivity to lower energies. The lowest energy threshold is obtained using monoscopic analysis of data taken with CT5, providing access to gamma-ray energies below 100 GeV for small zenith angle observations. Such an extension of the instrument's energy range is particularly beneficial for studies of active galactic nuclei with soft spectra, as expected for those at a redshift >= 0.5. The high-frequency peaked BL Lac objects PKS 2155-304 (z = 0.116) and PG 1553 + 113 (0.43 < z < 0.58) are among the brightest objects in the gamma-ray sky, both showing clear signatures of gamma-ray absorption at E > 100 GeV interpreted as being due to interactions with the extragalactic background light (EBL). Aims. The aims of this work are twofold: to demonstrate the monoscopic analysis of CT5 data with a low energy threshold, and to obtain accurate measurements of the spectral energy distributions (SED) of PKS 2155-304 and PG 1553 + 113 near their SED peaks at energies approximate to 100 GeV. Methods. Multiple observational campaigns of PKS 2155 304 and PG 1553 + 113 were conducted during 2013 and 2014 using the full H.E.S.S. II instrument (CT1-5). A monoscopic analysis of the data taken with the new CT5 telescope was developed along with an investigation into the systematic uncertainties on the spectral parameters which are derived from this analysis. Results. Using the data from CT5, the energy spectra of PKS 2155 304 and PG 1553 + 113 were reconstructed down to conservative threshold energies of 80 GeV for PKS 2155 304, which transits near zenith, and 110 GeV for the more northern PG 1553 + 113. The measured spectra, well fitted in both cases by a log-parabola spectral model ( with a 5.0 similar to statistical preference for non-zero curvature for PKS 2155 304 and 4.5 sigma for PG 1553+113), were found consistent with spectra derived from contemporaneous Fermi-LAT data, indicating a sharp break in the observed spectra of both sources at E approximate to 100 GeV. When corrected for EBL absorption, the intrinsic H.E.S.S. II mono and Fermi-LAT spectrum of PKS 2155 304 was found to show significant curvature. For PG 1553+113, however, no significant detection of curvature in the intrinsic spectrum could be found within statistical and systematic uncertainties.
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  • Abdo, A. A., et al. (författare)
  • FERMI Large Area Telescope and multi-wavelength observations of the flaring activity of PKS 1510-089 between 2008 september and 2009 june
  • 2010
  • Ingår i: Astrophysical Journal. - 0004-637X .- 1538-4357. ; 721:2, s. 1425-1447
  • Tidskriftsartikel (refereegranskat)abstract
    • We report on the multi-wavelength observations of PKS 1510-089 (a flat spectrum radio quasar (FSRQ) at z = 0.361) during its high activity period between 2008 September and 2009 June. During this 11 month period, the source was characterized by a complex variability at optical, UV, and gamma-ray bands, on timescales down to 6-12 hr. The brightest gamma-ray isotropic luminosity, recorded on 2009 March 26, was similar or equal to 2 x 1048 erg s-1. The spectrum in the Fermi Large Area Telescope energy range shows a mild curvature described well by a log-parabolic law, and can be understood as due to the Klein-Nishina effect. The. -ray flux has a complex correlation with the other wavelengths. There is no correlation at all with the X-ray band, a weak correlation with the UV, and a significant correlation with the optical flux. The. -ray flux seems to lead the optical one by about 13 days. From the UV photometry, we estimated a black hole mass of similar or equal to 5.4 x 10(8)M(circle dot) and an accretion rate of similar or equal to 0.5M(circle dot) yr(-1). Although the power in the thermal and non-thermal outputs is smaller compared to the very luminous and distant FSRQs, PKS 1510-089 exhibits a quite large Compton dominance and a prominent big blue bump (BBB) as observed in the most powerful gamma-ray quasars. The BBB was still prominent during the historical maximum optical state in 2009 May, but the optical/ UV spectral index was softer than in the quiescent state. This seems to indicate that the BBB was not completely dominated by the synchrotron emission during the highest optical state. We model the broadband spectrum assuming a leptonic scenario in which the inverse Compton emission is dominated by the scattering of soft photons produced externally to the jet. The resulting model-dependent jet energetic content is compatible with a scenario in which the jet is powered by the accretion disk, with a total efficiency within the Kerr black hole limit.
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  • Abdo, A. A., et al. (författare)
  • Gamma-ray emission concurrent with the nova in the symbiotic binary V407 cygni
  • 2010
  • Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 329:5993, s. 817-821
  • Tidskriftsartikel (refereegranskat)abstract
    • Novae are thermonuclear explosions on a white dwarf surface fueled by mass accreted from a companion star. Current physical models posit that shocked expanding gas from the nova shell can produce x-ray emission, but emission at higher energies has not been widely expected. Here, we report the Fermi Large Area Telescope detection of variable γ-ray emission (0.1 to 10 billion electron volts) from the recently detected optical nova of the symbiotic star V407 Cygni. We propose that the material of the nova shell interacts with the dense ambient medium of the red giant primary and that particles can be accelerated effectively to produce π0 decay γ-rays from proton-proton interactions. Emission involving inverse Compton scattering of the red giant radiation is also considered and is not ruled out.
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  • Abdo, A. A., et al. (författare)
  • Multi-wavelength observations of the flaring gamma-ray blazar 3C 66A in 2008 October
  • 2011
  • Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 726:1, s. 43-
  • Tidskriftsartikel (refereegranskat)abstract
    • The BL Lacertae object 3C 66A was detected in a flaring state by the Fermi Large Area Telescope (LAT) and VERITAS in 2008 October. In addition to these gamma-ray observations, F-GAMMA, GASP-WEBT, PAIRITEL, MDM, ATOM, Swift, and Chandra provided radio to X-ray coverage. The available light curves show variability and, in particular, correlated flares are observed in the optical and Fermi-LAT gamma-ray band. The resulting spectral energy distribution can be well fitted using standard leptonic models with and without an external radiation field for inverse Compton scattering. It is found, however, that only the model with an external radiation field can accommodate the intra-night variability observed at optical wavelengths.
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  • Abdo, A. A., et al. (författare)
  • The spectral energy distribution of fermi bright blazars
  • 2010
  • Ingår i: Astrophysical Journal. - 0004-637X .- 1538-4357. ; 716:1, s. 30-70
  • Tidskriftsartikel (refereegranskat)abstract
    • We have conducted a detailed investigation of the broadband spectral properties of the gamma-ray selected blazars of the Fermi LAT Bright AGN Sample (LBAS). By combining our accurately estimated Fermi gamma-ray spectra with Swift, radio, infra-red, optical, and other hard X-ray/gamma-ray data, collected within 3 months of the LBAS data taking period, we were able to assemble high-quality and quasi-simultaneous spectral energy distributions (SED) for 48 LBAS blazars. The SED of these gamma-ray sources is similar to that of blazars discovered at other wavelengths, clearly showing, in the usual log nu-log nu F-nu representation, the typical broadband spectral signatures normally attributed to a combination of low-energy synchrotron radiation followed by inverse Compton emission of one or more components. We have used these SED to characterize the peak intensity of both the low-and the high-energy components. The results have been used to derive empirical relationships that estimate the position of the two peaks from the broadband colors (i.e., the radio to optical, alpha(ro), and optical to X-ray, alpha(ox), spectral slopes) and from the gamma-ray spectral index. Our data show that the synchrotron peak frequency (nu(S)(peak)) is positioned between 10(12.5) and 10(14.5) Hz in broad-lined flat spectrum radio quasars (FSRQs) and between 10(13) and 10(17) Hz in featureless BL Lacertae objects. We find that the gamma-ray spectral slope is strongly correlated with the synchrotron peak energy and with the X-ray spectral index, as expected at first order in synchrotron-inverse Compton scenarios. However, simple homogeneous, one-zone, synchrotron self-Compton (SSC) models cannot explain most of our SED, especially in the case of FSRQs and low energy peaked (LBL) BL Lacs. More complex models involving external Compton radiation or multiple SSC components are required to reproduce the overall SED and the observed spectral variability. While more than 50% of known radio bright high energy peaked (HBL) BL Lacs are detected in the LBAS sample, only less than 13% of known bright FSRQs and LBL BL Lacs are included. This suggests that the latter sources, as a class, may be much fainter gamma-ray emitters than LBAS blazars, and could in fact radiate close to the expectations of simple SSC models. We categorized all our sources according to a new physical classification scheme based on the generally accepted paradigm for Active Galactic Nuclei and on the results of this SED study. Since the LAT detector is more sensitive to flat spectrum gamma-ray sources, the correlation between nu(S)(peak) and gamma-ray spectral index strongly favors the detection of high energy peaked blazars, thus explaining the Fermi overabundance of this type of sources compared to radio and EGRET samples. This selection effect is similar to that experienced in the soft X-ray band where HBL BL Lacs are the dominant type of blazars.
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  • Amon, B., et al. (författare)
  • From first-order logic to automated word generation for Lyee
  • 2003
  • Ingår i: Knowledge-Based Systems. - : Elsevier BV. - 0950-7051 .- 1872-7409. ; 16:07-8, s. 413-429
  • Tidskriftsartikel (refereegranskat)abstract
    • A conceptual schema can be viewed as a language to describe the phenomena in a system to be modelled, i.e. a set of derivation rules and integrity constraints as well as a set of event-rules describing the behaviour of an object system. In this paper, we investigate the relationship between the Lyee software requirements concepts with various constructs in conceptual modelling. Within our work we choose the Unified Modelling Language (UML) as a modelling notation for explaining conceptual models. The result obtained models a fully expressive set of UML and First Order Logic constructs mapped into Lyee concepts.
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  • Andersen, M. H. G., et al. (författare)
  • Exposure to Air Pollution inside Electric and Diesel-Powered Passenger Trains
  • 2019
  • Ingår i: Environmental Science & Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 53:8, s. 4579-4587
  • Tidskriftsartikel (refereegranskat)abstract
    • Diesel-powered trains are used worldwide for passenger transport. The present study aimed to assess air pollution concentrations in passenger cars from diesel and electric trains. Personal exposure monitoring (6-7 h per day) was carried out for 49 days on diesel and 22 days on electric trains. Diesel trains had higher concentrations of all the assessed air pollution components. Average increases (and fold differences) in passenger cars of diesel trains compared with electric trains were for ultrafine particles 212 000 particles/cm(3) (35-fold), black carbon 8.3 mu g/m(3) (6-fold), NOx 316 mu g/m(3) (8-fold), NO2 38 mu g/m(3) (3-fold), PM2.5 34 mu g/m(3) (2-fold), and benzo(a)pyrene 0.14 mu g/m(3) (6-fold). From time-series data, the pull and push movement modes, the engine in use, and the distance to the locomotive influenced the concentrations inside the diesel trains. In conclusion, concentrations of all air pollutants were significantly elevated in passenger cars in diesel trains compared to electric trains.
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  • Andersen, M. H. G., et al. (författare)
  • Health effects of exposure to diesel exhaust in diesel-powered trains
  • 2019
  • Ingår i: Particle and Fibre Toxicology. - : Springer Science and Business Media LLC. - 1743-8977. ; 16:21
  • Tidskriftsartikel (refereegranskat)abstract
    • BackgroundShort-term controlled exposure to diesel exhaust (DE) in chamber studies have shown mixed results on lung and systemic effects. There is a paucity of studies on well-characterized real-life DE exposure in humans. In the present study, 29 healthy volunteers were exposed to DE while sitting as passengers in diesel-powered trains. Exposure in electric trains was used as control scenario. Each train scenario consisted of three consecutive days (6h/day) ending with biomarker samplings.ResultsCombustion-derived air pollutants were considerably higher in the passenger carriages of diesel trains compared with electric trains. The concentrations of black carbon and ultrafine particles were 8.5g/m(3) and 1.2-1.8x10(5) particles/cm(3) higher, respectively, in diesel as compared to electric trains. Net increases of NOx and NO2 concentrations were 317g/m(3) and 36g/m(3). Exposure to DE was associated with reduced lung function and increased levels of DNA strand breaks in peripheral blood mononuclear cells (PBMCs), whereas there were unaltered levels of oxidatively damaged DNA, soluble cell adhesion molecules, acute phase proteins in blood and urinary excretion of metabolites of polycyclic aromatic hydrocarbons. Also the microvascular function was unaltered. An increase in the low frequency of heart rate variability measures was observed, whereas time-domain measures were unaltered.ConclusionExposure to DE inside diesel-powered trains for 3days was associated with reduced lung function and systemic effects in terms of altered heart rate variability and increased levels of DNA strand breaks in PBMCs compared with electric trains.Trial registrationClinicalTrials.Gov (NCT03104387). Registered on March 23rd 2017
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  • Delios, A., et al. (författare)
  • Examining the generalizability of research findings from archival data
  • 2022
  • Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 119:30
  • Tidskriftsartikel (refereegranskat)abstract
    • This initiative examined systematically the extent to which a large set of archival research findings generalizes across contexts. We repeated the key analyses for 29 original strategic management effects in the same context (direct reproduction) as well as in 52 novel time periods and geographies; 45% of the reproductions returned results matching the original reports together with 55% of tests in different spans of years and 40% of tests in novel geographies. Some original findings were associated with multiple new tests. Reproducibility was the best predictor of generalizability-for the findings that proved directly reproducible, 84% emerged in other available time periods and 57% emerged in other geographies. Overall, only limited empirical evidence emerged for context sensitivity. In a forecasting survey, independent scientists were able to anticipate which effects would find support in tests in new samples. 
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  • Gerdtham, U. G., et al. (författare)
  • The demand for health : Results from new measures of health capital
  • 1999
  • Ingår i: European Journal of Political Economy. - : Elsevier B.V. - 0176-2680 .- 1873-5703. ; 15:3, s. 501-521
  • Tidskriftsartikel (refereegranskat)abstract
    • This paper estimates a "Grossman" model of demand for health. We measure health status on a 0 (dead) to 1 (full health) cardinal scale by the rating scale method and the time trade-off method. We also use a categorical measure of overall health status commonly used in quality of life measurements. To estimate the demand for health equations, the Tobit technique is used for the rating scale and time trade-off health measure. The ordered probit model is used for the categorical health measure. The demand for health decreases with the price of medical care, age, overweight, smoking and living alone, and increases with income, education and the level of sporting activities.
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  • Ghosh, Swagatha, 1987, et al. (författare)
  • A simple goniometer-compatible flow cell for serial synchrotron X-ray crystallography
  • 2023
  • Ingår i: Journal of Applied Crystallography. - : International Union of Crystallography (IUCr). - 1600-5767. ; 56, s. 449-460
  • Tidskriftsartikel (refereegranskat)abstract
    • Serial femtosecond crystallography was initially developed for roomtemperature X-ray diffraction studies of macromolecules at X-ray free electron lasers. When combined with tools that initiate biological reactions within microcrystals, time-resolved serial crystallography allows the study of structural changes that occur during an enzyme catalytic reaction. Serial synchrotron X-ray crystallography (SSX), which extends serial crystallography methods to synchrotron radiation sources, is expanding the scientific community using serial diffraction methods. This report presents a simple flow cell that can be used to deliver microcrystals across an X-ray beam during SSX studies. This device consists of an X-ray transparent glass capillary mounted on a goniometercompatible 3D-printed support and is connected to a syringe pump via lightweight tubing. This flow cell is easily mounted and aligned, and it is disposable so can be rapidly replaced when blocked. This system was demonstrated by collecting SSX data at MAX IV Laboratory from microcrystals of the integral membrane protein cytochrome c oxidase from Thermus thermophilus, from which an X-ray structure was determined to 2.12 angstrom resolution. This simple SSX platform may help to lower entry barriers for non-expert users of SSX.
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  • Jafari, Rouhollah, et al. (författare)
  • Floquet dynamical quantum phase transitions under synchronized periodic driving
  • 2022
  • Ingår i: Physical Review B. - 2469-9950. ; 105:9
  • Tidskriftsartikel (refereegranskat)abstract
    • We study a generic class of fermionic two-band models under synchronized periodic driving, i.e., with the different terms in a Hamiltonian subject to periodic drives with the same frequency and phase. With all modes initially in a maximally mixed state, the synchronized drive is found to produce nonperiodic patterns of dynamical quantum phase transitions, with their appearance determined by an interplay of the band structure and the frequency of the drive. A case study of the anisotropic XY chain in a transverse magnetic field, transcribed to an effective two-band model, shows that the modes come with quantized geometric phases, allowing for the construction of an effective dynamical order parameter. Numerical studies in the limit of a strong magnetic field reveal distinct signals of precursors of dynamical quantum phase transitions also when the initial state of the XY chain is perturbed slightly away from maximal mixing, suggesting that the transitions may be accessible experimentally. A blueprint for an experiment built around laser-trapped circular Rydberg atoms is proposed.
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  • Joshi, Peter K, et al. (författare)
  • Directional dominance on stature and cognition in diverse human populations
  • 2015
  • Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 523:7561, s. 459-462
  • Tidskriftsartikel (refereegranskat)abstract
    • Homozygosity has long been associated with rare, often devastating, Mendelian disorders, and Darwin was one of the first to recognize that inbreeding reduces evolutionary fitness. However, the effect of the more distant parental relatedness that is common in modern human populations is less well understood. Genomic data now allow us to investigate the effects of homozygosity on traits of public health importance by observing contiguous homozygous segments (runs of homozygosity), which are inferred to be homozygous along their complete length. Given the low levels of genome-wide homozygosity prevalent in most human populations, information is required on very large numbers of people to provide sufficient power. Here we use runs of homozygosity to study 16 health-related quantitative traits in 354,224 individuals from 102 cohorts, and find statistically significant associations between summed runs of homozygosity and four complex traits: height, forced expiratory lung volume in one second, general cognitive ability and educational attainment (P < 1 × 10(-300), 2.1 × 10(-6), 2.5 × 10(-10) and 1.8 × 10(-10), respectively). In each case, increased homozygosity was associated with decreased trait value, equivalent to the offspring of first cousins being 1.2 cm shorter and having 10 months' less education. Similar effect sizes were found across four continental groups and populations with different degrees of genome-wide homozygosity, providing evidence that homozygosity, rather than confounding, directly contributes to phenotypic variance. Contrary to earlier reports in substantially smaller samples, no evidence was seen of an influence of genome-wide homozygosity on blood pressure and low density lipoprotein cholesterol, or ten other cardio-metabolic traits. Since directional dominance is predicted for traits under directional evolutionary selection, this study provides evidence that increased stature and cognitive function have been positively selected in human evolution, whereas many important risk factors for late-onset complex diseases may not have been.
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  • Mirastschijski, U, et al. (författare)
  • Effect of a matrix metalloproteinase activity and TNF-alpha converting enzyme inhibitor on intra-abdominal adhesions.
  • 2005
  • Ingår i: European Surgical Research. - : S. Karger AG. - 0014-312X .- 1421-9921. ; 37:1, s. 68-75
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND: Formation of intra-abdominal adhesions depends, in part, on the activity of serine proteinases. Matrix metalloproteinases (MMP) are required for epithelialization of skin wounds but their involvement in mesothelialization of peritoneal wounds and in adhesion pathogenesis is not known. Early tumor necrosis factor-alpha (TNF-alpha) levels have been proposed to reflect propensity to adhesion formation. OBJECTIVE: The impact of MMP activity and secreted TNF-alpha on peritoneal adhesion formation and healing was investigated through systemic administration of the synthetic broad-spectrum MMP and TNF-alpha-converting enzyme (TACE) inhibitor GM 6001. METHODS: Female Sprague-Dawley rats of 4-6 weeks of age were injected subcutaneously daily with GM 6001 100 mg/kg (n = 12) or vehicle (n = 10) starting two days before surgery. In each rat, two standardized peritoneal wounds, 20 mm x 5 mm, were made. One peritoneal wound was sutured whereas the contralateral wound healed by secondary intention. Adhesion formation and peritoneal healing, cell proliferation, and hydroxyproline concentrations were evaluated on postoperative day 7. RESULTS: Total serum TNF-alpha levels increased in vehicle-treated rats (p = 0.019) while GM 6001 treatment effectively prevented the rise in the postoperative phase (p < 0.001). No significant differences were observed in the extent of adhesion formation (p = 0.67) between control (65.0%) and GM 6001-treated (61.5%) animals, or peritoneal wound healing or cell proliferation. Hydroxyproline levels increased in the wounds (p = 0.014) but were not different between the two groups (p = 0.14). CONCLUSIONS: Lack of a striking effect of the MMP and TACE antagonist GM 6001 on postoperative adhesions suggests that MMP activity and TNF-alpha might not be major adhesiogenic factors.
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  • Molnár, Peter, 1967, et al. (författare)
  • Source Apportionment of PM2.5 Using Positive Matrix Factorization (PMF) and PMF with Factor Selection
  • 2014
  • Ingår i: Aerosol and Air Quality Research. - : Taiwan Association for Aerosol Research. - 1680-8584 .- 2071-1409. ; 14:3
  • Tidskriftsartikel (refereegranskat)abstract
    • Personal exposure, indoor, residential outdoor and urban background particulate matter (PM2.5) samples were collected in parallel, for 30 participants and analyzed for their chemical content. Source apportionments for the separate microenvironments were performed using conventional positive matrix factorization (PMF), and for the combined dataset, applying a new PMF method with factor selection. Regional sources were the largest contributor to the sampled PM2.5 in all microenvironments and accounted for 69% in urban background; 55% and 54% in residential outdoor and indoor environment, respectively; and 40% of personal exposure. For personal exposure, personal activities accounted for 21% (2.2 mu g/m(3)), and constituted the main difference in total mass concentration between personal exposure and the other microenvironments. The PMF method with factor selection was found to be a useful tool in the PMF analysis of multiple microenvironments, since ambient contributions to indoor and personal exposure are less likely to be distorted or misinterpreted. The possibility to more correctly estimate the source contributions will increase by combining the datasets for the different microenvironments into a larger dataset and using the PMF with factor selection method.
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45.
  • Olafsson, S, et al. (författare)
  • Fourteen sequence variants that associate with multiple sclerosis discovered by meta-analysis informed by genetic correlations
  • 2017
  • Ingår i: NPJ genomic medicine. - : Springer Science and Business Media LLC. - 2056-7944. ; 2, s. 24-
  • Tidskriftsartikel (refereegranskat)abstract
    • A meta-analysis of publicly available summary statistics on multiple sclerosis combined with three Nordic multiple sclerosis cohorts (21,079 cases, 371,198 controls) revealed seven sequence variants associating with multiple sclerosis, not reported previously. Using polygenic risk scores based on public summary statistics of variants outside the major histocompatibility complex region we quantified genetic overlap between common autoimmune diseases in Icelanders and identified disease clusters characterized by autoantibody presence/absence. As multiple sclerosis-polygenic risk scores captures the risk of primary biliary cirrhosis and vice versa (P = 1.6 × 10−7, 4.3 × 10−9) we used primary biliary cirrhosis as a proxy-phenotype for multiple sclerosis, the idea being that variants conferring risk of primary biliary cirrhosis have a prior probability of conferring risk of multiple sclerosis. We tested 255 variants forming the primary biliary cirrhosis-polygenic risk score and found seven multiple sclerosis-associating variants not correlated with any previously established multiple sclerosis variants. Most of the variants discovered are close to or within immune-related genes. One is a low-frequency missense variant in TYK2, another is a missense variant in MTHFR that reduces the function of the encoded enzyme affecting methionine metabolism, reported to be dysregulated in multiple sclerosis brain.
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46.
  • Panova, M, et al. (författare)
  • DNA Extraction Protocols for Whole-Genome Sequencing in Marine Organisms
  • 2016
  • Ingår i: Marine Genomics - Methods and Protocols. - New York, NY : Springer New York. - 1064-3745. - 9781493937721 - 9781493937745 ; 1452, s. 13-44
  • Bokkapitel (refereegranskat)abstract
    • The marine environment harbors a large proportion of the total biodiversity on this planet, including the majority of the earths’ different phyla and classes. Studying the genomes of marine organisms can bring interesting insights into genome evolution. Today, almost all marine organismal groups are understudied with respect to their genomes. One potential reason is that extraction of high-quality DNA in sufficient amounts is challenging for many marine species. This is due to high polysaccharide content, polyphenols and other secondary metabolites that will inhibit downstream DNA library preparations. Consequently, protocols developed for vertebrates and plants do not always perform well for invertebrates and algae. In addition, many marine species have large population sizes and, as a consequence, highly variable genomes. Thus, to facilitate the sequence read assembly process during genome sequencing, it is desirable to obtain enough DNA from a single individual, which is a challenge in many species of invertebrates and algae. Here, we present DNA extraction protocols for seven marine species (four invertebrates, two algae, and a marine yeast), optimized to provide sufficient DNA quality and yield for de novo genome sequencing projects.
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