| 1. |
- Adloff, C, et al.
(författare)
-
A measurement of the t dependence of the helicity structure of diffractive rho meson electroproduction at HERA
- 2002
-
Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - 0370-2693. ; 539:1-2, s. 25-39
-
Tidskriftsartikel (refereegranskat)abstract
- The helicity structure of the diffractive electroproduction of rho mesons, e + p --> e + rho + Y, is studied in a previously unexplored region of large four-momentum transfer squared at the proton vertex, t: 0 < t' < 3 GeV2, where t' = - min. The data used are collected with the HI detector at HERA in the kinematic domain 2.5 < Q(2) < 60 GeV2, 40 < W < 120 GeV No t dependence of the r(00)(04) spin density matrix element is found. A significant t dependent helicity non-conservation from the virtual photon to the rho meson is observed for the spin density matrix element combinations r(00)(5) + 2r(11)(5) and r(00)(1) + 2r(11)(1). These t dependences are consistently described by a perturbative QCD model based on the exchange of two gluons.
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| 2. |
- Adloff, C, et al.
(författare)
-
Diffractive photoproduction of psi(2S) mesons at HERA
- 2002
-
Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - 0370-2693. ; 541:3-4, s. 251-264
-
Tidskriftsartikel (refereegranskat)abstract
- Results on diffractive photoproduction of psi(2S) mesons are presented using data collected between 1996 and 2000 with the H1 detector at the HERA ep collider. The data correspond to an integrated luminosity of 77 pb(-1). The energy dependence of the diffractive psi(2S) cross section is found to be similar to or possibly somewhat steeper than that for J/psi mesons. The dependences of the elastic and proton dissociative psi(2S) photoproduction cross sections on the squared momentum transfer t at the proton vertex are measured. The t-dependence of the elastic channel, parametrised as e(bt), yields b(el)(psi(2S)) = (4.31 +/- 0.57 +/- 0.46) GeV-2, compatible with that of the J/psi. For the proton dissociative channel the result b(pd)(psi(2S)) = (0.59 +/- 0.13 +/- 0.12) GeV-2 is 2.3 standard deviations smaller than that measured for the J/psi. With proper account of the individual wavefunctions theoretical predictions based on perturbative QCD are found to describe the measurements well. (C) 2002 Elsevier Science B.V. All rights reserved.
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| 3. |
- Adloff, C, et al.
(författare)
-
Energy flow and rapidity gaps between jets in photoproduction at HERA
- 2002
-
Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 24:4, s. 517-527
-
Tidskriftsartikel (refereegranskat)abstract
- Dijet events in photon-proton collisions in which there is a large pseudorapidity separation, Deltaeta > 2.5 between the two highest E-T jets are studied with the H1 detector at HERA. The inclusive dijet cross sections are measured as functions of the longitudinal momentum fractions of the proton and photon which participate in the production of the jets, x(p)(jets) and x(gamma)(jets) respectively, Deltaeta, the pseudorapidity P separation between the two highest E-T jets, and E-T(gap), the total summed transverse energy between the jets. Rapidity gap events are defined as events in which E-T(gap) is less than E-T(cut), for E-T(cut) varied between jets 0.5 and 2.0 GeV. The fraction of dijet events with a rapidity gap is measured differentially in Deltaeta, x(p)(jets) and x(gamma)(jets). An excess of events with rapidity gaps at low values of E-T(cut) is observed above the expectation from standard photoproduction processes. This excess can be explained by the exchange of a strongly interacting colour singlet object between the jets.
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| 4. |
- Adloff, C, et al.
(författare)
-
Inelastic photoproduction of J/psi mesons at HERA
- 2002
-
Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 25:1, s. 25-39
-
Tidskriftsartikel (refereegranskat)abstract
- An analysis of inelastic photoproduction of J/psi mesons is presented using data collected at the ep collider HERA corresponding to an integrated luminosity of above 80 pb(-1), Differential and double I < P-t/psi(2) < differential cross sections are measured in a wide kinematic region: 60 < W-gammap < 260 GeV, 1 p(t,psi)(2) < 60 GeV2 and 0.05 < z < 0.9. where z is the fraction of the energy of the exchanged photon transferred to the J/psi meson in the rest frame of the target proton. Cross sections at z less than or similar to 0.3 are presented for the first time. Theoretical calculations within the Colour Singlet Model at NLO for direct photon processes are shown to give a good description of the data in the medium z region (0.3 < z < 0.9) up to the highest p(t,psi)(2) values. A calculation using a k(t) factorisation approach in LO in the Colour Singlet Model is also able to describe these data. The data in the full z range are also compared to LO calculations within a non-relativistic QCD framework including colour octet and colour singlet contributions for direct and resolved photons. It seems possible to reconcile data and theory with modest contributions from colour octet processes. The polarisation of the J/psi meson is measured as a function of z and p(t,psi) and is reasonably described by the theoretical predictions.
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| 5. |
- Adloff, C, et al.
(författare)
-
Measurement of D*(+/-) meson production and F-2(c) in deep-inelastic scattering at HERA
- 2002
-
Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - 0370-2693. ; 528:3-4, s. 199-214
-
Tidskriftsartikel (refereegranskat)abstract
- The inclusive production of D*+/-(2010) mesons in deep-inelastic scattering is studied with the HI detector at HERA. In the kinematic region 1 < Q(2) < 100 GeV2 and 0.05 < y < 0.7 an e(+) p cross section for inclusive D*+/- meson production of 8.50 +/- 0.42(stat.)(-100)(+1.21)(syst.) nb is measured in the visible range p(tD*) > 1.5 GeV and eta(D*) < 1.5. Single and double differential inclusive D*+/- meson cross sections are compared to perturbative QCD calculations in two different evolution schemes, The charm contribution to the proton structure, F-c(2)(x, Q(2)), is determined by extrapolating the visible charm cross section to the full phase space. This contribution is found to rise from about 10% at Q(2) = 1.5 GeV2 to more than 25% at Q(2) = 60 GeV2 corresponding to x values ranging from 5 x 10(-5) to 3 x 10(-3). (C) 2002 Elsevier Science B.V. All rights reserved.
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| 6. |
- Adloff, C, et al.
(författare)
-
Measurement of dijet cross sections in photoproduction at HERA
- 2002
-
Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 25:1, s. 13-23
-
Tidskriftsartikel (refereegranskat)abstract
- Dijet cross sections as functions of several jet observables are measured in photoproduction using the HI detector at HERA. The data sample comprises e(+)p data with an integrated luminosity of 319 pb(-1). Jets are selected using the inclusive k(perpendicular to) algorithm with a minimum transverse energy of 25 GeV for the leading jet. The phase space covers longitudinal proton momentum fraction x(p) and photon longitudinal momentum fraction x(gamma) in the ranges 0.05 < x(p) < 0.6 and 0.1 < x(gamma) < 1. The predict ions of next-to-leading order perturbative QCD, including recent photon and proton parton densities, are found to be compatible with the data in a wide kinematical range.
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| 7. |
- Adloff, C, et al.
(författare)
-
Measurement of dijet electroproduction at small jet separation
- 2002
-
Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 24:1, s. 33-41
-
Tidskriftsartikel (refereegranskat)abstract
- Deep-inelastic scattering data in the range 150 < Q(2) < 35000 GeV2 are used to investigate the minimum jet separation necessary to allow accurate description of the rate of dijet production using next-to-leading order perturbative QCD calculations. The required jet separation is found to be small, allowing about 1/3 of DIS data to be classified as dijet, as opposed to approximately 1/10 with more typical jet analyses. A number of precision measurements made using this dijet sample are well described by the calculations. The data are also described by the combination of leading order matrix elements and parton showers, as implemented in the QCD based Monte Carlo model RAPGAP.
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| 8. |
- Adloff, C, et al.
(författare)
-
Measurement of inclusive jet cross-sections in deep-inelastic ep scattering at HERA
- 2002
-
Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - 0370-2693. ; 542:3-4, s. 193-206
-
Tidskriftsartikel (refereegranskat)abstract
- A measurement of inclusive jet cross-sections in deep-inelastic ep scattering at HERA is presented based on data with an integrated luminosity of 21.1 pb(-1). The measurement is performed for photon virtualities Q(2) between 5 and 100 GeV2, differentially in Q(2), in the jet transverse energy E-T, in E-T(2)/Q(2) and in the pseudorapidity eta(lab). With the renormalization scale mu(R) = E-T, perturbative QCD calculations in next-to-leading order (NLO) give a good description of the data in most of the phase space. Significant discrepancies are observed only for jets in the proton beam direction with ET below 20 GeV and Q2 below 20 GeV2. This corresponds to the region in which NLO corrections are largest and further improvement of the calculations is thus of particular interest.
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| 9. |
- Adloff, C, et al.
(författare)
-
Search for excited neutrinos at HERA
- 2002
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Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - 0370-2693. ; 525:1-2, s. 9-16
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Tidskriftsartikel (refereegranskat)abstract
- We present a search for excited neutrinos using e(-) p data taken by the H1 experiment at HERA at a center-of-mass energy of 318 GeV with an integrated luminosity of 15 pb(-1). No evidence for excited neutrino production is found. Mass dependent exclusion limits are determined for the ratio of the coupling to the compositeness scale, f/Lambda, independently of the relative couplings to the SU(2) and U(1) gauge bosons. These limits extend the excluded region to higher masses than has been possible in previous searches at other colliders.
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| 10. |
- Adloff, C, et al.
(författare)
-
Search for odderon-induced contributions to exclusive pi(0) photoproduction at HERA
- 2002
-
Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - 0370-2693. ; 544:1-2, s. 35-43
-
Tidskriftsartikel (refereegranskat)abstract
- A search for contributions to the reaction ep --> epi(0)N* from photon-odderon fusion in the photoproduction regime at HERA is reported, at an average photon-proton centre-of-mass energy = 215 GeV. The measurement proceeds via detection of the pi(0) decay photons, a leading neutron from the N* decay, and the scattered electron. No pi(0) signal is observed and an upper limit on the cross section for the photon-odderon fusion process of sigma(gammap --> pi(0)N*) < 49 nb at the 95% confidence level is derived, integrated over the experimentally accessible range of the squared four-momentum transfer at the nucleon vertex 0.02 < < 0.3 GeV2. This excludes a recent prediction from a calculation based on a non-perturbative QCD model of a photon-odderon fusion cross section above 200 nb. (C) 2002 Elsevier Science B.V. All rights reserved.
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| 11. |
- Adloff, C, et al.
(författare)
-
Search for QCD instanton-induced processes in deep-inelastic scattering at HERA
- 2002
-
Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 25:4, s. 495-509
-
Tidskriftsartikel (refereegranskat)abstract
- Signals of QCD instanton-induced processes are searched for in deep-inelastic scattering (DIS) at the electron-proton collider HERA in a kinematic region defined by the Bjorken-scaling variables x > 10(-3), 0.1 < y < 0.6 and photon virtualities 10 less than or similar to Q(2) < 100 GeV2. Several observables characterising hadronic final state properties of QCD instanton-induced events are exploited to identify a potentially instanton-enriched domain. While an excess of events with instanton-like topology is observed it cannot be claimed significant given the uncertainty of the standard DIS background simulation. Upper limits on the cross-section for instanton-induced processes of between 60 pb and 1000 pb are set dependent on the kinematic domain considered. The data do not exclude the cross-section predicted by instanton perturbation theory for small instanton sizes. At large instanton sizes a naive extrapolation of instanton perturbation theory yields a cross-section in the range of sensitivity of this study. Such a cross-section is not observed, in agreement with non-perturbative lattice simulations of the QCD vacuum.
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| 12. |
- Adloff, C, et al.
(författare)
-
Inelastic leptoproduction of J/psi mesons at HERA
- 2002
-
Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 25:1, s. 41-53
-
Tidskriftsartikel (refereegranskat)abstract
- The leptoproduction of J/psi mesons is studied in inelastic reactions for four momentorri transfers 2 < Q(2) < 100GeV(2). The data were taken with the H1 detector at the electron proton collider HERA and correspond to an integrated luminosity of 77 pb(-1). Single differential and double differential cross sections are measured with increased precision compared with previous analyses. New leading order calculations within the non-relativistic QCD factorisation approach including colour octet and colour singlet contributions are compared with the data and are found to give a reasonable description of most distributions. An exception is the shape of the distribution in the J/psi fractional energy. z, which deviates significantly from that of the data. Comparisons with photoproduction are made and the polarisation of the produced J/psi meson is analysed.
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| 13. |
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| 14. |
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| 15. |
- Sarneel, Judith M., et al.
(författare)
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Reading tea leaves worldwide : decoupled drivers of initial litter decomposition mass-loss rate and stabilization
- 2024
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Ingår i: Ecology Letters. - : John Wiley & Sons. - 1461-023X .- 1461-0248. ; 27:5
-
Tidskriftsartikel (refereegranskat)abstract
- The breakdown of plant material fuels soil functioning and biodiversity. Currently, process understanding of global decomposition patterns and the drivers of such patterns are hampered by the lack of coherent large-scale datasets. We buried 36,000 individual litterbags (tea bags) worldwide and found an overall negative correlation between initial mass-loss rates and stabilization factors of plant-derived carbon, using the Tea Bag Index (TBI). The stabilization factor quantifies the degree to which easy-to-degrade components accumulate during early-stage decomposition (e.g. by environmental limitations). However, agriculture and an interaction between moisture and temperature led to a decoupling between initial mass-loss rates and stabilization, notably in colder locations. Using TBI improved mass-loss estimates of natural litter compared to models that ignored stabilization. Ignoring the transformation of dead plant material to more recalcitrant substances during early-stage decomposition, and the environmental control of this transformation, could overestimate carbon losses during early decomposition in carbon cycle models.
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| 16. |
- Strassman, Alexander, et al.
(författare)
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Generation of a multipurpose Prdm16 mouse allele by targeted gene trapping
- 2017
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Ingår i: Disease Models and Mechanisms. - : The Company of Biologists. - 1754-8403 .- 1754-8411. ; 10:7, s. 909-922
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Tidskriftsartikel (refereegranskat)abstract
- Gene trap mutagenesis is a powerful tool to create loss-of-function mutations in mice and other model organisms. Modifications of traditional gene trap cassettes, including addition of conditional features in the form of Flip-excision (FlEx) arrays to enable directional gene trap cassette inversions by Cre and Flpe site-specific recombinases, greatly enhanced their experimental potential. By taking advantage of these conditional gene trap cassettes, we developed a generic strategy for generating conditional mutations and validated this strategy in mice carrying a multipurpose allele of the Prdm16 transcription factor gene. We demonstrate that the gene trap insertion creates a null mutation replicating the Pierre Robin sequence-type cleft palate phenotype of other Prdm16 mutant mice. Consecutive breeding to Flpe and Emx1(IREScre) deleter mice spatially restricted Prdm16 loss to regions of the forebrain expressing the homeobox gene Emx1, demonstrating the utility of the technology for the analysis of tissue-specific gene functions.
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| 17. |
- Carter, M. S., et al.
(författare)
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Synthesizing greenhouse gas fluxes across nine European peatlands and shrublands - responses to climatic and environmental changes
- 2012
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Ingår i: Biogeosciences. - : Copernicus GmbH. - 1726-4189. ; 9:10, s. 3739-3755
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we compare annual fluxes of methane (CH4), nitrous oxide (N2O) and soil respiratory carbon dioxide (CO2) measured at nine European peatlands (n = 4) and shrublands (n = 5). The sites range from northern Sweden to Spain, covering a span in mean annual air temperature from 0 to 16 degrees C, and in annual precipitation from 300 to 1300 mm yr(-1). The effects of climate change, including temperature increase and prolonged drought, were tested at five shrubland sites. At one peatland site, the long-term (> 30 yr) effect of drainage was assessed, while increased nitrogen deposition was investigated at three peatland sites. The shrublands were generally sinks for atmospheric CH4, whereas the peatlands were CH4 sources, with fluxes ranging from -519 to + 6890 mg CH4-Cm-2 yr(-1) across the studied ecosystems. At the peatland sites, annual CH4 emission increased with mean annual air temperature, while a negative relationship was found between net CH4 uptake and the soil carbon stock at the shrubland sites. Annual N2O fluxes were generally small ranging from -14 to 42 mg N2O-Nm(-2) yr(-1). Highest N2O emission occurred at the sites that had highest nitrate (NO3-) concentration in the soil water. Furthermore, experimentally increased NO3- deposition led to increased N2O efflux, whereas prolonged drought and long-term drainage reduced the N2O efflux. Soil CO2 emissions in control plots ranged from 310 to 732 g CO2-C m(-2) yr(-1). Drought and long-term drainage from -519 to + 6890 mg CH4-C m(-2) yr(-1) across the studied ecosystems. At the peatland sites, annual CH4 emission increased with mean annual air temperature, while a negative relationship was found between net CH4 uptake and the soil carbon stock at the shrubland sites. Annual N2O fluxes were generally small ranging from -14 to 42 mg N2O-N m(-2) yr(-1). Highest N2O emission occurred at the sites that had highest nitrate (NO3-) concentration in the soil water. Furthermore, experimentally increased NO3- deposition led to increased N2O efflux, whereas prolonged drought and long-term drainage reduced the N2O efflux. Soil CO2 emissions in control plots ranged from 310 to 732 g CO2-Cm-2 yr(-1). Drought and long-term drainage generally reduced the soil CO2 efflux, except at a hydric shrubland where drought tended to increase soil respiration. In terms of fractional importance of each greenhouse gas to the total numerical global warming response, the change in CO2 efflux dominated the response in all treatments (ranging 71-96%), except for NO3- addition where 89% was due to change in CH4 emissions. Thus, in European peatlands and shrublands the effect on global warming induced by the investigated anthropogenic disturbances will be dominated by variations in soil CO2 fluxes.
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| 18. |
- Hovenden, Mark J., et al.
(författare)
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Globally consistent influences of seasonal precipitation limit grassland biomass response to elevated CO2
- 2019
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Ingår i: Nature Plants. - : Springer Science and Business Media LLC. - 2055-0278. ; 5, s. 167-173
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Tidskriftsartikel (refereegranskat)abstract
- © 2019, The Author(s), under exclusive licence to Springer Nature Limited. Rising atmospheric carbon dioxide concentration should stimulate biomass production directly via biochemical stimulation of carbon assimilation, and indirectly via water savings caused by increased plant water-use efficiency. Because of these water savings, the CO 2 fertilization effect (CFE) should be stronger at drier sites, yet large differences among experiments in grassland biomass response to elevated CO 2 appear to be unrelated to annual precipitation, preventing useful generalizations. Here, we show that, as predicted, the impact of elevated CO 2 on biomass production in 19 globally distributed temperate grassland experiments reduces as mean precipitation in seasons other than spring increases, but that it rises unexpectedly as mean spring precipitation increases. Moreover, because sites with high spring precipitation also tend to have high precipitation at other times, these effects of spring and non-spring precipitation on the CO 2 response offset each other, constraining the response of ecosystem productivity to rising CO 2 . This explains why previous analyses were unable to discern a reliable trend between site dryness and the CFE. Thus, the CFE in temperate grasslands worldwide will be constrained by their natural rainfall seasonality such that the stimulation of biomass by rising CO 2 could be substantially less than anticipated.
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| 19. |
- Mikkelsen, T N, et al.
(författare)
-
Experimental design of multifactor climate change experiments with elevated CO2, warming and drought: the CLIMAITE project
- 2008
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Ingår i: Functional Ecology. - : Wiley. - 1365-2435 .- 0269-8463. ; 22:1, s. 185-195
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Tidskriftsartikel (refereegranskat)abstract
- Recent findings indicate that the interactions among CO2, temperature and water can be substantial, and that the combined effects on the biological systems of several factors may not be predicted from experiments with one or a few factors. Therefore realistic multifactorial experiments involving a larger set of main factors are needed. We describe a new Danish climate change-related field scale experiment, CLIMAITE, in a heath/grassland ecosystem. CLIMAITE is a full factorial combination of elevated CO2, elevated temperature and prolonged summer drought. The manipulations are intended to mimic anticipated major environmental changes at the site by year 2075 as closely as possible. The impacts on ecosystem processes and functioning (at ecophysiological levels, through responses by individuals and communities to ecosystem-level responses) are investigated simultaneously. The increase of [CO2] closely corresponds with the scenarios for year 2075, while the warming treatment is at the lower end of the predictions and seems to be the most difficult treatment to increase without unwanted side effects on the other variables. The drought treatment follows predictions of increased frequency of drought periods in summer. The combination of the treatments does not create new unwanted side effects on the treatments relative to the treatments alone.
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| 20. |
- Schon, M P, et al.
(författare)
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Mucosal T lymphocyte numbers are selectively reduced in integrin alpha E (CD103)-deficient mice
- 1999
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Ingår i: Journal of Immunology. - 1550-6606. ; 162:11, s. 6641-6649
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Tidskriftsartikel (refereegranskat)abstract
- The mucosal lymphocyte integrin alpha E(CD103)beta 7 is thought to be important for intraepithelial lymphocyte (IEL) localization or function. We cloned the murine integrin gene encoding alpha E, localized it to chromosome 11, and generated integrin alpha E-deficient mice. In alpha E-/- mice, intestinal and vaginal IEL numbers were reduced, consistent with the known binding of alpha E beta 7 to E-cadherin expressed on epithelial cells. However, it was surprising that lamina propria T lymphocyte numbers were diminished, as E-cadherin is not expressed in the lamina propria. In contrast, peribronchial, intrapulmonary, Peyer's patch, and splenic T lymphocyte numbers were not reduced in alpha E-deficient mice. Thus, alpha E beta 7 was important for generating or maintaining the gut and vaginal T lymphocytes located diffusely within the epithelium or lamina propria but not for generating the gut-associated organized lymphoid tissues. Finally, the impact of alpha E deficiency upon intestinal IEL numbers was greater at 3-4 wk of life than in younger animals, and affected the TCR alpha beta+ CD8+ T cells more than the gamma delta T cells or the TCR alpha beta+ CD4+CD8- population. These findings suggest that alpha E beta 7 is involved in the expansion/recruitment of TCR alpha beta+ CD8+ IEL following microbial colonization. Integrin alpha E-deficient mice will provide an important tool for studying the role of alpha E beta 7 and of alpha E beta 7-expressing mucosal T lymphocytes in vivo.
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| 21. |
- Andresen, Louise C., 1974, et al.
(författare)
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Moderate nitrogen retention in temperate heath ecosystem after elevated CO2, drought and warming through 7years
- 2023
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Ingår i: European Journal of Soil Science. - 1351-0754 .- 1365-2389. ; 74:4
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Tidskriftsartikel (refereegranskat)abstract
- Nitrogen (N) dynamic is one of the main controlling factors of responses to climate change in N-limited terrestrial ecosystems, which rely on nutrient re-cycling and retention. In this study we investigate the N partitioning in ecosystem compartments of a grassland heath, and the impact of multiple climate change factors on long-term N retention after 15N pulse labelling. The impacts of elevated carbon dioxide (eCO2), warming and drought and the treatments in combination on ecosystem N retention was investigated in a field scale manipulation experiment. A six-year time-course was assessed by pulse-labelling with the stable N isotope 15N and by sampling after 1 day, 1 year and 6years. After the six years we observed that the total ecosystem retained 42 % of the amended 15N across treatments (recovery of the amended 15N in the pool). The fate of the applied 15N was mainly stabilisation in soil, with 36 % recovery, while the plant compartment and microbial biomass each retained only 1-2 % of the added 15N. This suggests a moderate retention of N, for all treatments, as compared to similar long-term studies of forest ecosystems. A decreased ammonium and vegetation N pool combined with higher 15N retention in the soil at eCO2 treatments suggests that eCO2 promoted processes that immobilize N in soil, while warming counteracted this when combined with eCO2. Drought treatments contrastingly increased the vegetation N pool. We conclude that as the organic soil layer has the main capacity for N storage in a temperate heathland-grassland, it is important for buffering nutrient availability and maintaining a resilient ecosystem. However, the full treatment combination of drought, warming and eCO2 did not differ in 15N recovery from the controls, suggesting unchanged long-term consequences of climate change on retention of pulse added N in this ecosystem.
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| 22. |
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| 23. |
- Beier, S., et al.
(författare)
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The environment drives microbial trait variability in aquatic habitats
- 2020
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Ingår i: Molecular Ecology. - : Wiley. - 0962-1083 .- 1365-294X.
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Tidskriftsartikel (refereegranskat)abstract
- A prerequisite to improve the predictability of microbial community dynamics is to understand the mechanisms of microbial assembly. To study factors that contribute to microbial community assembly, we examined the temporal dynamics of genes in five aquatic metagenome time-series, originating from marine offshore or coastal sites and one lake. With this trait-based approach we expected to find gene-specific patterns of temporal allele variability that depended on the seasonal metacommunity size of carrier-taxa and the variability of the milieu and the substrates to which the resulting proteins were exposed. In more detail, we hypothesized that a larger seasonal metacommunity size would result in increased temporal variability of functional units (i.e., gene alleles), as shown previously for taxonomic units. We further hypothesized that multicopy genes would feature higher temporal variability than single-copy genes, as gene multiplication can result from high variability in substrate quality and quantity. Finally, we hypothesized that direct exposure of proteins to the extracellular environment would result in increased temporal variability of the respective gene compared to intracellular proteins that are less exposed to environmental fluctuations. The first two hypotheses were confirmed in all data sets, while significant effects of the subcellular location of gene products was only seen in three of the five time-series. The gene with the highest allele variability throughout all data sets was an iron transporter, also representing a target for phage infection. Previous work has emphasized the role of phage–prokaryote interactions as a major driver of microbial diversity. Our finding therefore points to a potentially important role of iron transporter-mediated phage infections for the assembly and maintenance of diversity in aquatic prokaryotes.
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| 24. |
- Hakkarainen, M, et al.
(författare)
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The clinical picture of ERCC6L2 disease: from bone marrow failure to acute leukemia
- 2023
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Ingår i: Blood. - : American Society of Hematology. - 1528-0020 .- 0006-4971. ; 141:23, s. 2853-2866
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Tidskriftsartikel (refereegranskat)abstract
- Biallelic germline ERCC6L2 variants strongly predispose to bone marrow failure (BMF) and myeloid malignancies characterized by somatic TP53-mutated clones and erythroid predominance. We present a series of 52 subjects (35 families) with ERCC6L2 biallelic germline variants collected retrospectively in 11 centers globally, including follow-up of 1165 person-years. At initial investigations, 32 individuals were diagnosed with BMF and 15 with a hematological malignancy (HM). Subjects presented with 19 different variants across ERCC6L2, and we identified a founder mutation c.1424delT in the Finnish patients. The median age of subjects at baseline was 18 years (range 2-65). Changes in complete blood count (CBC) were mild despite severe bone marrow hypoplasia and somatic TP53 mutations, with no significant difference between subjects with or without (HM). Signs of a progressive disease were increasing TP53 variant allele frequency, dysplasia in megakaryocytes and/or erythroid lineage, and erythroid predominance in bone marrow morphology. The median age at onset of HM was 37.0 years (95% CI: 31.5-42.5; range 12-65). Overall survival (OS) at 3 years was 95% (95% CI: 85-100) and 19% (95% CI: 0-39) for patients with BMF and HM, respectively. Patients with myelodysplastic syndrome or acute myeloid leukemia with mutated TP53 undergoing hematopoietic stem cell transplantation had a poor outcome: 3-year OS is 28% (95% CI: 0-61). Our results demonstrate the importance of early recognition and active surveillance of patients with biallelic germline ERCC6L2 variants.
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| 25. |
- Hakkarainen, M, et al.
(författare)
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The clinical picture of ERCC6L2 disease: from bone marrow failure to acute leukemia
- 2023
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Ingår i: Blood. - : American Society of Hematology. - 1528-0020 .- 0006-4971. ; 141:23, s. 2853-2866
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Tidskriftsartikel (refereegranskat)abstract
- Biallelic germline ERCC6L2 variants strongly predispose to bone marrow failure (BMF) and myeloid malignancies characterized by somatic TP53-mutated clones and erythroid predominance. We present a series of 52 subjects (35 families) with ERCC6L2 biallelic germline variants collected retrospectively in 11 centers globally, including follow-up of 1165 person-years. At initial investigations, 32 individuals were diagnosed with BMF and 15 with a hematological malignancy (HM). Subjects presented with 19 different variants across ERCC6L2, and we identified a founder mutation c.1424delT in the Finnish patients. The median age of subjects at baseline was 18 years (range 2-65). Changes in complete blood count (CBC) were mild despite severe bone marrow hypoplasia and somatic TP53 mutations, with no significant difference between subjects with or without (HM). Signs of a progressive disease were increasing TP53 variant allele frequency, dysplasia in megakaryocytes and/or erythroid lineage, and erythroid predominance in bone marrow morphology. The median age at onset of HM was 37.0 years (95% CI: 31.5-42.5; range 12-65). Overall survival (OS) at 3 years was 95% (95% CI: 85-100) and 19% (95% CI: 0-39) for patients with BMF and HM, respectively. Patients with myelodysplastic syndrome or acute myeloid leukemia with mutated TP53 undergoing hematopoietic stem cell transplantation had a poor outcome: 3-year OS is 28% (95% CI: 0-61). Our results demonstrate the importance of early recognition and active surveillance of patients with biallelic germline ERCC6L2 variants.
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| 26. |
- Heidenreich, N., et al.
(författare)
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A multi-purpose reaction cell for the investigation of reactions under solvothermal conditions
- 2017
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Ingår i: Review of Scientific Instruments. - : AIP Publishing. - 0034-6748 .- 1089-7623. ; 88:10
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Tidskriftsartikel (refereegranskat)abstract
- A new versatile and easy-to-use remote-controlled reactor setup aimed at the analysis of chemical reactions under solvothermal conditions has been constructed. The reactor includes a heating system that can precisely control the temperature inside the reaction vessels in a range between ambient temperature and 180 degrees C. As reaction vessels, two sizes of commercially available borosilicate vessels (V-max = 5 and 11 ml) can be used. The setup furthermore includes the option of stirring and injecting of up to two liquid additives or one solid during the reaction to initiate very fast reactions, quench reactions, or alter chemical parameters. In addition to a detailed description of the general setup and its functionality, three examples of studies conducted using this setup are presented.
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| 27. |
- Holmstrup, Martin, et al.
(författare)
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Long-term and realistic global change manipulations had low impact on diversity of soil biota in temperate heathland
- 2017
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- In a dry heathland ecosystem we manipulated temperature (warming), precipitation (drought) and atmospheric concentration of CO2 in a full-factorial experiment in order to investigate changes in below-ground biodiversity as a result of future climate change. We investigated the responses in community diversity of nematodes, enchytraeids, collembolans and oribatid mites at two and eight years of manipulations. We used a structural equation modelling (SEM) approach analyzing the three manipulations, soil moisture and temperature, and seven soil biological and chemical ariables. The analysis revealed a persistent and positive effect of elevated CO2 on litter C:N ratio. After two years of treatment, the fungi to bacteria ratio was increased by warming, and the diversities within oribatid mites, collembolans and nematode groups were all affected by elevated CO2 mediated through increased litter C:N ratio. After eight years of treatment, however, the CO2-increased litter C:N ratio did not influence the diversity in any of the four fauna groups. The number of significant correlations between treatments, food source quality, and soil biota diversities was reduced from six to three after two and eight years, respectively. These results suggest a remarkable resilience within the soil biota against global climate change treatments in the long term.
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| 28. |
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| 29. |
- Lankester, Arjan C, et al.
(författare)
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Hematopoietic cell transplantation in severe combined immunodeficiency: The SCETIDE 2006-2014 European cohort.
- 2022
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Ingår i: The Journal of allergy and clinical immunology. - : Elsevier BV. - 1097-6825 .- 0091-6749. ; 149:5
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Tidskriftsartikel (refereegranskat)abstract
- Hematopoietic stem cell transplantation (HSCT) represents a curative treatment for patients with severe combined immunodeficiency (SCID), a group of monogenic immune disorders with an otherwise fatal outcome.We performed a comprehensive multicenter analysis of genotype-specific HSCT outcome, including detailed analysis of immune reconstitution (IR) and the predictive value for clinical outcome.HSCT outcome was studied in 338 patients with genetically confirmed SCID who underwent transplantation in 2006-2014 and who were registered in the SCETIDE registry. In a representative subgroup of 152 patients, data on IR and long-term clinical outcome were analyzed.Two-year OS was similar with matched family and unrelated donors and better than mismatched donor HSCT (P<.001). The 2-year event-free survival (EFS) was similar in matched and mismatched unrelated donor and less favorable in mismatched related donor (MMRD) HSCT (P< .001). Genetic subgroups did not differ in 2-year OS (P= .1) and EFS (P=.073). In multivariate analysis, pretransplantation infections and use of MMRDs were associated with less favorable OS and EFS. With a median follow-up of 6.2 years (range, 2.0-11.8 years), 73 of 152 patients in the IR cohort were alive and well without Ig dependency. IL-2 receptor gamma chain/Janus kinase 3/IL-7 receptor-deficient SCID, myeloablative conditioning, matched donor HSCT, and naive CD4 T lymphocytes >0.5×10e3/μL at+1 year were identified as independent predictors of favorable clinical and immunologic outcome.Recent advances in HSCT in SCID patients have resulted in improved OS and EFS in all genotypes and donor types. To achieve a favorable long-term outcome, treatment strategies should aim for optimal naive CD4 T lymphocyte regeneration.
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| 30. |
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| 31. |
- Walse, Charlotta, et al.
(författare)
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Modelling ''clean rain'' treatments in acidified soils - EXMAN project results
- 1995
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Ingår i: Water, Air and Soil Pollution. - 1573-2932. ; 85:3, s. 1807-1812
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Tidskriftsartikel (refereegranskat)abstract
- The SAFE dynamic model was applied to a ''clean rain'' roof experiment performed within the EXMAN project. In the experiment ambient throughfall was removed and replaced with artificial ''clean throughfall''. Input of S, N and H to the forest ecosystem was reduced by 75-100%. The results of the modelling show, that the time scales of model predictions and experiments are the same. The change in base cation flux was well reproduced, while the simulation of changes in aluminum flux was less successful. pH stayed constant in the experiment as well as in the calculations.
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| 32. |
- Wu, J., et al.
(författare)
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Modelling the decadal trend of ecosystem carbon fluxes demonstrates the important role of functional changes in a temperate deciduous forest
- 2013
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Ingår i: Ecological Modelling. - : Elsevier. - 0304-3800 .- 1872-7026. ; 260, s. 50-61
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Tidskriftsartikel (refereegranskat)abstract
- Temperate forests are globally important carbon sinks and stocks. Trends in net ecosystem exchange have been observed in a Danish beech forest and this trend cannot be entirely attributed to changing climatic drivers. This study sought to clarify the mechanisms responsible for the observed trend, using a dynamic ecosystem model (CoupModel) and model data fusion with multiple constraints and model experiments. Experiments with different validation datasets showed that a multiple constraints model data fusion approach that included the annual tree growth, the seasonal canopy development, the latent and sensible heat fluxes and the CO2 fluxes decreased the parameter uncertainty considerably compared to using CO2 fluxes as validation data alone. The fitted model was able to simulate the observed carbon fluxes well (R-2 = 0.8, mean error = 0.1 g C m(-2) d(-1)) but did not reproduce the decadal (1997-2009) trend in carbon uptake when global parameter estimates were used. Annual parameter estimates were able to reproduce the decadal scale trend; the yearly fitted posterior parameters (e.g. the light use efficiency) indicated a role for changes in the ecosystem functional properties. A possible role for nitrogen demand during mast years is supported by the inter-annual variability in the estimated parameters. The inter-annual variability of photosynthesis parameters was fundamental to the simulation of the trend in carbon fluxes in the investigated beech forest and this demonstrates the importance of functional change in carbon balance.
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