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Sökning: WFRF:(Kroon Johan)

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1.
  • Kroon, Johan, et al. (författare)
  • Increasing production value in Scots pine plantation through mixing with lodgepole pine
  • 2019
  • Ingår i: Scandinavian Journal of Forest Research. - : Taylor & Francis Group. - 0282-7581 .- 1651-1891. ; 34:8, s. 689-698
  • Tidskriftsartikel (refereegranskat)abstract
    • Mixing tree species could be a silviculture model that allows early harvest of short-rotation trees, while longer-rotation crop trees remain in the stand. We examined the effects on growth and tree characteristics in a planted experiment with lodgepole pine (LP) and elite-bred Scots pine (SP) in mixed (50/50) and monospecific plots in three different spacings (at 28 years of age after planting). The future development under different thinning regimes, including net present value for one rotation, was analyzed using the Heureka simulation software. As expected, LP had higher survival and initially more rapid growth than SP, with highest stand productivity and biomass production in LP monoculture during a rotation period as a result. However, intimate mixtures of SP and LP at the two widest spacings could give greater production and economic benefits, compared to SP in monoculture. It seems that elite-bred SP will differ in competitiveness against LP, depending on spacing for growth and some quality traits (branch and bark thickness, height of green crown). The findings support developing management systems for combining sparsely planted, and expensive, elite-bred SP in mixture with other trees that maintains high stem volume production and secures certain properties of trees and stands.
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2.
  • Andersson, R., et al. (författare)
  • Modeling of free fatty acid dynamics: insulin and nicotinic acid resistance under acute and chronic treatments
  • 2017
  • Ingår i: Journal of Pharmacokinetics and Pharmacodynamics. - : Springer Science and Business Media LLC. - 1573-8744 .- 1567-567X. ; 44:3, s. 203-222
  • Tidskriftsartikel (refereegranskat)abstract
    • Nicotinic acid (NiAc) is a potent inhibitor of adipose tissue lipolysis. Acute administration results in a rapid reduction of plasma free fatty acid (FFA) concentrations. Sustained NiAc exposure is associated with tolerance development (drug resistance) and complete adaptation (FFA returning to pretreatment levels). We conducted a meta-analysis on a rich pre-clinical data set of the NiAc-FFA interaction to establish the acute and chronic exposure-response relations from a macro perspective. The data were analyzed using a nonlinear mixed-effects framework. We also developed a new turnover model that describes the adaptation seen in plasma FFA concentrations in lean Sprague-Dawley and obese Zucker rats following acute and chronic NiAc exposure. The adaptive mechanisms within the system were described using integral control systems and dynamic efficacies in the traditional model. Insulin was incorporated in parallel with NiAc as the main endogenous co-variate of FFA dynamics. The model captured profound insulin resistance and complete drug resistance in obese rats. The efficacy of NiAc as an inhibitor of FFA release went from 1 to approximately 0 during sustained exposure in obese rats. The potency of NiAc as an inhibitor of insulin and of FFA release was estimated to be 0.338 and 0.436 , respectively, in obese rats. A range of dosing regimens was analyzed and predictions made for optimizing NiAc delivery to minimize FFA exposure. Given the exposure levels of the experiments, the importance of washout periods in-between NiAc infusions was illustrated. The washout periods should be 2 h longer than the infusions in order to optimize 24 h lowering of FFA in rats. However, the predicted concentration-response relationships suggests that higher AUC reductions might be attained at lower NiAc exposures.
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3.
  • Bengtsson, Samuel N., et al. (författare)
  • Free induction decay in the extreme ultraviolet
  • 2015
  • Ingår i: Proceedings of Frontiers in Optics 2015, FIO 2015. - 9781943580033
  • Konferensbidrag (refereegranskat)abstract
    • We present an experimental study of controlled Free Induction Decay (FID) in the extreme ultraviolet regime excited by High-order Harmonics. The control is done by applying a delayed infrared pulse.
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4.
  • Brizuela, Fernando, et al. (författare)
  • Efficient high order harmonic generation boosted by below threshold harmonics
  • 2013
  • Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 3
  • Tidskriftsartikel (refereegranskat)abstract
    • High-order harmonic generation (HHG) in gases has been established as an important technique for the generation of coherent extreme ultraviolet (XUV) pulses at ultrashort time scales. Its main drawback, however, is the low conversion efficiency, setting limits for many applications, such as ultrafast coherent imaging, nonlinear processes in the XUV range, or seeded free electron lasers. Here we introduce a novel scheme based on using below-threshold harmonics, generated in a seeding cell, to boost the HHG process in a generation cell, placed further downstream in the focused laser beam. By modifying the fundamental driving field, these low-order harmonics alter the ionization step of the nonlinear HHG process. Our dual-cell scheme enhances the conversion efficiency of HHG, opening the path for the realization of robust intense attosecond XUV sources.
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5.
  • de Kroon, Hans, et al. (författare)
  • Elasticities : a review of methods and model limitations
  • 2000
  • Ingår i: Ecology. - 0012-9658 .- 1939-9170. ; 81:3, s. 607-618
  • Tidskriftsartikel (refereegranskat)abstract
    • Elasticity is a perturbation measure in matrix projection models that quantifiesthe proportional change in population growth rate as a function of a proportionalchange in a demographic transition (growth, survival, reproduction, etc.). Elasticities thusindicate the relative "importance" of life cycle transitions for population growth and maintenance.In this paper, we discuss the applications of elasticity analysis, and its extension,loop analysis, in life history studies and conservation. Elasticity can be interpreted as therelative contribution of a demographic parameter to population growth rate. Loop analysisreveals the underlying pathway structure of the life cycle graph. The different kinds ofresults of the two analyses in studies of life histories are emphasized. Because elasticitiesquantify the relative importance of life cycle transitions to population growth rate, it isgenerally inferred that management should focus on the transitions with the largest elasticities.Such predictions based on elasticities seem robust, but we do identify three situationswhere problems may arise. The mathematical properties and biological constraints thatunderlie these pitfalls are explained. Examples illustrate the additional information thatneeds to be taken into account for a sensible use of elasticities in population management.We conclude by indicating topics that are in need of research.
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6.
  • Fries, Anders, et al. (författare)
  • Stem damage of lodgepole pine clonal cuttings in relation to wood and fiber traits, acoustic velocity, and spiral grain
  • 2014
  • Ingår i: Scandinavian Journal of Forest Research. - : Informa UK Limited. - 0282-7581 .- 1651-1891. ; 29, s. 764-776
  • Tidskriftsartikel (refereegranskat)abstract
    • Eight clones from a 16-year-old field trial of clonal cuttings of lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) were analyzed for growth, growth pattern, and stem damage in the field. In addition, wood and fiber traits (acoustic velocity [AcVel] and spiral grain) were analyzed and wood density, microfibril angle, modulus of elasticity, and radial fiber diameter (FibDR) determined from SilviScan analyzes. Two clones with considerably more bent, broken, and leaning stems differed from the other clones in terms of microfibril angle and modulus of elasticity (MOE) in the outermost annual rings. FibDR and, to some extent, MOE in the outermost annual rings were negatively correlated with the frequency of bent, leaning, or broken stems, while microfibril angle (MFA) was positively correlated. AcVel was negatively correlated with both MFA and the frequency of bent, broken, and leaning stems. We conclude that AcVel could be used as an effective tool to predict severe stem damage and determine stem strength in the field instead of using costly lab-based SilviScan measurements of microfibril angle. If developed further, this approach could be used for large-scale screening of progeny tests when selecting for stem strength.
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7.
  • Guenot, Diego, et al. (författare)
  • Measurements of relative photoemission time delays in noble gas atoms
  • 2014
  • Ingår i: Journal of Physics B. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 47:24, s. 245602-
  • Tidskriftsartikel (refereegranskat)abstract
    • We determine relative photoemission time delays between valence electrons in different noble gas atoms (Ar, Ne and He) in an energy range between 31 and 37 eV. The atoms are ionized by an attosecond pulse train synchronized with an infrared laser field and the delays are measured using an interferometric technique. We compare our results with calculations using the random phase approximation with exchange and multi-configurational Hartree-Fock. We also investigate the influence of the different ionization angular channels.
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8.
  • Guenot, Diego, et al. (författare)
  • Photoemission time delay measurements and calculations close to the 3s ionization cross section minimum in ar
  • 2012
  • Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - 1050-2947 .- 1094-1622. ; 85:5, s. 053424-
  • Tidskriftsartikel (refereegranskat)abstract
    • We present experimental measurements and theoretical calculations of photoionization time delays from the 3s and 3p shells in Ar in the photon energy range of 32-42 eV. The experimental measurements are performed by interferometry using attosecond pulse trains and the infrared laser used for their generation. The theoretical approach includes intershell correlation effects between the 3s and 3p shells within the framework of the random-phase approximation with exchange. The connection between single-photon ionization and the two-color two-photon ionization process used in the measurement is established using the recently developed asymptotic approximation for the complex transition amplitudes of laser-assisted photoionization. We compare and discuss the theoretical and experimental results, especially in the region where strong intershell correlations in the 3s -> kp channel lead to an induced Cooper minimum in the 3s ionization cross section.
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9.
  • Hall, David, 1974-, et al. (författare)
  • Divergent patterns between phenotypic and genetic variation in Scots pine
  • 2021
  • Ingår i: Plant Communications. - : Elsevier. - 2590-3462. ; 2:1
  • Tidskriftsartikel (refereegranskat)abstract
    • In boreal forests, autumn frost tolerance in seedlings is a critical fitness component because it determines survival rates during regeneration. To understand the forces that drive local adaptation in this trait, we conducted freezing tests in a common garden setting for 54 Pinus sylvestris (Scots pine) populations (>5000 seedlings) collected across Scandinavia into western Russia, and genotyped 24 of these populations (>900 seedlings) at >10 000 SNPs. Variation in cold hardiness among populations, as measured by QST, was above 80% and followed a distinct cline along latitude and longitude, demonstrating significant adaptation to climate at origin. In contrast, the genetic differentiation was very weak (mean FST 0.37%). Despite even allele frequency distribution in the vast majority of SNPs among all populations, a few rare alleles appeared at very high or at fixation in marginal populations restricted to northwestern Fennoscandia. Genotype–environment associations showed that climate variables explained 2.9% of the genetic differentiation, while genotype–phenotype associations revealed a high marker-estimated heritability of frost hardiness of 0.56, but identified no major loci. Very extensive gene flow, strong local adaptation, and signals of complex demographic history across markers are interesting topics of forthcoming studies on this species to better clarify signatures of selection and demography.
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10.
  • Hayatgheibi, Haleh, et al. (författare)
  • Estimation of genetic parameters, provenance performances, and genotype by environment interactions for growth and stiffness in lodgepole pine (Pinus contorta)
  • 2019
  • Ingår i: Scandinavian Journal of Forest Research. - : Informa UK Limited. - 0282-7581 .- 1651-1891. ; 34, s. 1-11
  • Tidskriftsartikel (refereegranskat)abstract
    • Genetic parameters, performance of provenances, and genotype by environment interaction (GxE) for diameter at breast height (DBH), survival, and modulus of elasticity of time-of-flight (MOEtof) (an indirect measure of stiffness), were investigated in six lodgepole pine progeny trials, aged 33-36 years, within three breeding zones in northern Sweden. Provenances of Yukon origin had the highest growth but lowest stiffness at higher latitude, while those of British Columbia (BC) origin grew faster at lower latitudes and had highest stiffness within zone 5.Combined-site heritability estimates ranged from 0.09 to 0.19 for DBH, from 0.19 to 0.27 for MOEtof, and from 0.13 to 0.26 for survival. Type-B genetic correlations () were generally high for all studied traits, except for DBH and survival in zone 4 (=0.74 and 0.40, respectively) and for MOEtof in zone 2 (=0.46). On the basis of the results obtained in this study, GxE for stiffness in northern Sweden and unfavourable growth-stiffness genetic correlation should be considered in selective breeding programmes of lodgepole pine. To achieve the highest stiffness for lodgepole pine, provenances of Yukon origin should be planted at lower latitudes and those of BC origin should be planted at lower elevations within the tested breeding zones.
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11.
  • Hayatgheibi, Haleh, et al. (författare)
  • Genetic analysis of lodgepole pine (Pinus contorta) solid-wood quality traits
  • 2017
  • Ingår i: Canadian Journal of Forest Research. - : Canadian Science Publishing. - 0045-5067 .- 1208-6037. ; 47, s. 1303-1313
  • Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
    • Potential improvement of lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) solid-wood properties was examined by estimating age trends of inheritance, age-age genetic correlations, and the efficiency of early selection using 823 increment cores sampled from 207 half-sib families at two independent progeny trials, aged 34-35 years, located in northern Sweden. High-resolution radial variation of annual ring width, wood density, microfibril angle (MFA), and modulus of elasticity (clearwood stiffness; MOES) was measured using SilviScan. The dynamic stiffness (MOEtof) of standing trees was also obtained using Hitman ST300. Heritabilities ranged from 0.10 to 0.64 for growth and earlywood, transition-wood, and latewood proportions, from 0.29 to 0.77 for density traits, and from 0.13 to 0.33 for MFA and stiffness traits. Genetic correlations between early age and the reference age (26 years) suggested that early selection is efficient at age 4 years for MFA and between ages 5 to 8 years for density and MOES. Unfavorable diameter-stiffness genetic correlations and correlated responses indicate that breeding for a 1% increase in diameter would confer 5.5% and 2.3% decreases in lodgepole pine MOES and MOEtof, respectively. Index selection with appropriate economical weights for growth and wood stiffness is highly recommended for selective breeding.
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12.
  • Jimenez-Galan, A., et al. (författare)
  • Phase Measurement of a Fano Resonance Using Tunable Attosecond Pulses
  • 2015
  • Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 635, s. 092137-092137
  • Konferensbidrag (refereegranskat)abstract
    • We study photoionization of argon atoms close to the 3s(2)3p(6) -> 3s(1)3p(6)4p Fano resonance using an attosecond pulse train and a weak infrared probe field. An interferometric technique combined with tunable attosecond pulses allows us to determine the phase of the photoionization amplitude as a function of photon energy. We interpret the experimental results using an analytical two-photon model based on the Fano formalism and obtain quantitative agreement.
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13.
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14.
  • Kotur, Marija, et al. (författare)
  • Spectral phase measurement of a Fano resonance using tunable attosecond pulses
  • 2016
  • Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 7
  • Tidskriftsartikel (refereegranskat)abstract
    • Electron dynamics induced by resonant absorption of light is of fundamental importance in nature and has been the subject of countless studies in many scientific areas. Above the ionization threshold of atomic or molecular systems, the presence of discrete states leads to autoionization, which is an interference between two quantum paths: direct ionization and excitation of the discrete state coupled to the continuum. Traditionally studied with synchrotron radiation, the probability for autoionization exhibits a universal Fano intensity profile as a function of excitation energy. However, without additional phase information, the full temporal dynamics cannot be recovered. Here we use tunable attosecond pulses combined with weak infrared radiation in an interferometric setup to measure not only the intensity but also the phase variation of the photoionization amplitude across an autoionization resonance in argon. The phase variation can be used as a fingerprint of the interactions between the discrete state and the ionization continua, indicating a new route towards monitoring electron correlations in time.
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15.
  • Kroon, David, et al. (författare)
  • Attosecond pulse walk-off in high-order harmonic generation
  • 2014
  • Ingår i: Optics Letters. - 0146-9592. ; 39:7, s. 2218-2221
  • Tidskriftsartikel (refereegranskat)abstract
    • We study the influence of the generation conditions on the group delay of attosecond pulses in high-order harmonic generation in gases. The group delay relative to the fundamental field is found to decrease with increasing gas pressure in the generation cell, reflecting a temporal walk-off due to the dispersive properties of the nonlinear medium. This effect is well reproduced using an on-axis phase-matching model of high-order harmonic generation in an absorbing gas. (C) 2014 Optical Society of America
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16.
  • Kroon, Johan, et al. (författare)
  • Estimation of Clonal Variation in Seed Cone Production Over Time in a Scots pine (Pinus sylvestris L.) Seed Orchard
  • 2009
  • Ingår i: Silvae Genetica. - : Walter de Gruyter GmbH. - 0037-5349 .- 2509-8934. ; 58, s. 53-62
  • Tidskriftsartikel (refereegranskat)abstract
    • Possibilities for early selection of clones for future seed cone production were studied in a clonal seed orchard of Scots pine (Pinus sylvestris L.) in northern Sweden over the first 30 years following establishment. The annual data were modelled as series of bivariate analyses. The correlations between cone production of clones in any individual year and that of a previous year, and cumulative cone production over all years were studied. The corresponding multivariate analysis for a full data fit simultaneously was best estimated with a genetic distance-based power model (AR). The genetic (variation among clones) and environmental variation were of the same magnitude. The genetic correlations were larger than the phenotypic correlations and both increased with orchard age. Basing selection of clones on a single observation at an early age to improve future cone production was not effective, but efficiency increased if cumulative cone count over many years was used. Year-to-year genetic correlations indicated that early forecasts by clone of cone production at mature ages are highly uncertain. Reliable predictions (moderate correlations) could be achieved only if based on rather mature grafts, 14 or more years after establishment.
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17.
  • Kroon, Johan (författare)
  • Spatiotemporal patterns of genetic variation for growth and fertility in Scots pine
  • 2011
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Genetic testing plays an important role in tree breeding. Understanding basic genetic parameters for growth and fertility is a prerequisite for developing a successful breeding strategy to balance between short- and long-term gains. It is both impractical and inefficient to wait until trials are several decades old to make selection decisions. It is therefore of great value to evaluate a sample of long-term experiments to confirm selection efficiency at ages closer to rotation time. This thesis investigates the genetic expression of field performance in Scots pine (Pinus sylvestris L.) for growth and fertility in long-term experiments over time and across sites. The data revealed large variation in genetic expression over time and across sites. The additive effect was the most important source of genetic variation for growth, while estimates of dominance were small, site-specific, and decreased much with age. Thus, there is little benefit in attempting to explore dominance through specific combining ability to improve genetic productivity in northern Sweden. Progeny of plus-trees selected in northern Sweden showed faster growth compared to unimproved controls at age 30, as well as genetic differences in stem shape, such that improved trees were more slender. The genetic relationship between height and diameter in northern Sweden demonstrated the importance of considering diameter in selection to obtain greater genetic gain in volume. Overall, the results show higher heritability at older ages and genetic correlations that reveal important rank changes with time and across environments. Clonal variation in female fertility in mature seed orchards is rather small and varies as much within clones as among clones, and is heavily dependent on year of assessment. The prospects for early selection of clones for future seed cone production based on a single-year observation are low. Finally, this thesis illustrates the importance of subjecting data from long-term field tests to a multi-trait, multi-site analysis accounting for environmental effects.
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18.
  • Kroon, Tobias, et al. (författare)
  • Dosing profile profoundly influences nicotinic acid's ability to improve metabolic Control in rats
  • 2015
  • Ingår i: Journal of Lipid Research. - 0022-2275 .- 1539-7262. ; 56, s. 1679-1690
  • Tidskriftsartikel (refereegranskat)abstract
    • Acute nicotinic acid (NiAc) administration results in rapid reduction of plasma FFA concentrations. However, sustained NiAc exposure is associated with tolerance development resulting in return of FFA to pretreatment levels. The aim of this study was to determine whether a 12 h rectangular exposure profile (intermittent dose group) could avoid tolerance development and thereby reverse insulin resistance induced by lipid overload. FFA lowering was assessed in male Sprague Dawley (lean) and obese Zucker rats (obese) in response to a 5 h NiAc infusion, in either NiAc-naive animals or after 5 days of continuous (24 h/day) or intermittent (12 h/day) NiAc dosing (via implantable, programmable minipump). We found that intermittent dosing over 5 days preserved NiAc-induced FFA lowering, comparable to dosing in NiAc-naive animals. By contrast, following 5 days continuous administration, NiAc-induced FFA lowering was lost. The effect of intermittent NiAc infusion on insulin sensitivity was assessed in obese Zucker rats using hyperinsulinemic-isoglycemic clamps. The acute effect of NiAc to elevate glucose infusion rate (vs. saline control) was indeed preserved with intermittent dosing, while being lost upon continuous infusion. In conclusion, an intermittent but not continuous NiAc dosing strategy succeeded in retaining NiAc's ability to lower FFA and improve insulin sensitivity in obese Zucker rats.Kroon, T., A. Kjellstedt, P. Thalen, J. Gabrielsson, and N. D. Oakes.
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19.
  • Kroon, Tobias, et al. (författare)
  • Feedback modeling of non-esterified fatty acids in obese Zucker rats after nicotinic acid infusions
  • 2013
  • Ingår i: Journal of Pharmacokinetics and Pharmacodynamics. - : Springer Science and Business Media LLC. - 1567-567X .- 1573-8744. ; 40, s. 623-638
  • Tidskriftsartikel (refereegranskat)abstract
    • This study investigates the impact of disease on nicotinic acid (NiAc)-induced changes in plasma concentrations of non-esterified fatty acids (NEFA). NiAc was given by constant intravenous infusion to normal Sprague-Dawley and obese Zucker rats, and arterial blood samples were taken for analysis of NiAc, NEFA, insulin and glucose plasma concentrations. The intravenous route was intentionally selected to avoid confounding processes, such as absorption, following extravascular administration. Data were analyzed using nonlinear mixed effects modeling (NONMEM, version VI). The disposition of NiAc in the normal rats was described by a two-compartment model with endogenous synthesis of NiAc and two parallel capacity-limited elimination processes. In the obese rats disposition was described by a one-compartment model with endogenous synthesis of NiAc and one capacity-limited elimination process. The plasma concentration of NiAc drove NEFA (R) turnover via an inhibitory drug-mechanism function acting on the formation of NEFA. NEFA turnover was described by a feedback model with a moderator distributed over a series of transit compartments, where the first compartment (M (1) ) inhibited the formation of R and the last compartment (M (N) ) stimulated the loss of R. All processes regulating plasma NEFA concentrations were assumed to be captured by the moderator function. Differences in the pharmacodynamic response of the two strains included, in the obese animals, an increased NEFA baseline, diminished rebound and post-rebound oscillation, and a more pronounced slowly developing tolerance during the period of constant drug exposure. The feedback model captured the NiAc-induced changes in NEFA response in both the normal and obese rats. Differences in the parameter estimates between the obese and normal rats included, in the former group, increases in R (0) , k (in) and p by 44, 41 and 78 %, respectively, and decreases in k (out) and gamma by 64 and 84 %, respectively. The estimates of k (tol) and IC (50) were similar in both groups. The NiAc-NEFA concentration-response relationship at equilibrium was substantially different in the two groups, being shifted upwards and to the right, and being shallower in the obese rats. The extent of such shifts is important, as they demonstrate the impact of disease at equilibrium and, if ignored, will lead to erroneous dose predictions and, in consequence, poorly designed studies. The proposed models are primarily aimed at screening and selecting candidates with the highest potential of becoming a viable drug in man.
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20.
  • Kroon, Tobias, et al. (författare)
  • Nicotinic acid timed to feeding reverses tissue lipid accumulation and improves glucose control in obese Zucker rats
  • 2017
  • Ingår i: Journal of Lipid Research. - 0022-2275 .- 1539-7262. ; 58, s. 31-41
  • Tidskriftsartikel (refereegranskat)abstract
    • Nicotinic acid (NiAc) is a potent inhibitor of lipolysis, acutely reducing plasma free fatty acid (FFA) concentrations. However, a major FFA rebound is seen during rapid NiAc washout, and sustained exposure is associated with tolerance development, with FFAs returning to pretreatment levels. Our aim was to find a rational NiAc dosing regimen that preserves FFA lowering, sufficient to reverse nonadipose tissue lipid accumulation and improve metabolic control, in obese Zucker rats. We compared feeding-period versus fasting-period NiAc dosing for 5 days: 12 h subcutaneous infusion (programmable, implantable mini-pumps) terminated by gradual withdrawal. It was found that NiAc timed to feeding decreased triglycerides in liver (-47%; P < 0.01) and heart (-38%; P < 0.05) and reduced plasma fructosamine versus vehicle. During oral glucose tolerance test, plasma FFA levels were reduced with amelioration of hyperglycemia and hypertriglyceridemia. Furthermore, timing NiAc to feeding resulted in a general downregulation of de novo lipogenesis (DNL) genes in liver. By contrast, NiAc timed to fasting did not reduce tissue lipids, ameliorate glucose intolerance or dyslipidemia, or alter hepatic DNL genes.(Jlr) In conclusion, NiAc dosing regimen has a major impact on metabolic control in obese Zucker rats. Specifically, a well-defined NiAc exposure, timed to feeding periods, profoundly improves the metabolic phenotype of this animal model.
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21.
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22.
  • Kroon, Åsa, 1967-, et al. (författare)
  • How slow is ‘slow TV’? Audiences’ experiences of meditation, obsession and authenticity when watching swimming moose on Swedish television
  • 2023
  • Ingår i: Journal of Popular Television. - : Intellect Ltd.. - 2046-9861 .- 2046-987X. ; 11:3, s. 279-298
  • Tidskriftsartikel (refereegranskat)abstract
    • This article explores viewers’ experiences of the Swedish Public Service (SVT) ‘slow TV’ broadcast Den stora älgvandringen (The Great Moose Migration), aired as a three-week long, live, multi-platform programme since 2019. Through semi-structured interviews with key informants, the aim is to qualitatively under- stand the audience attraction to the 24/7 programme, especially when it comes to authenticity, affordances and its apparent slowness of pace. The study showcases a spectrum of audiences’ experiences, ranging from appreciating the programme’s serenity and stillness to its potential for unexpected drama. It is suggested thatThe Great Moose Migration offers a ‘direct’ link to Swedish nature as it enables awallowing in Swedish landscapes and fauna, and allows for an unashamed adora- tion of the majestic Swedish moose, but without it being experienced as something particularly ‘Swedish’. It is found that authenticity is central to the programme’s success with both production team and audiences. However, both personal and sociable experiences of the programme as authentic rest on the collective accept- ance of authenticity as something intrinsically produced by people and technolo- gies yet not experienced as constructed. Rather, it is something that hovers in between experienced mediated and unmediated reality.
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23.
  • Louisy, Maite, et al. (författare)
  • Gating attosecond pulses in a noncollinear geometry
  • 2015
  • Ingår i: Optica. - 2334-2536. ; 2:6, s. 563-566
  • Tidskriftsartikel (refereegranskat)abstract
    • The efficient generation of isolated attosecond pulses (IAPs), giving access to ultrafast electron dynamics in various systems, is a key challenge in attosecond science. IAPs can be produced by confining the extreme ultraviolet emission generated by an intense laser pulse to a single field half-cycle or, as shown recently, by employing angular streaking methods. Here, we experimentally demonstrate the angular streaking of attosecond pulse trains in a noncollinear geometry, leading to the emission of angularly separated IAPs. The noncollinear geometry simplifies the separation of the fundamental laser field and the generated pulses, making this scheme promising for intracavity attosecond pulse generation, thus opening new possibilities for high-repetition-rate attosecond sources. (C) 2015 Optical Society of America
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24.
  • Neophytou, Charalambos, et al. (författare)
  • Molecular Genetic Identification Explains Differences in Bud Burst Timing among Progenies of Selected Trees of the Swedish Douglas Fir Breeding Programme
  • 2022
  • Ingår i: Forests. - : MDPI. - 1999-4907. ; 13:6
  • Tidskriftsartikel (refereegranskat)abstract
    • Douglas fir is expected to play an increasingly important role in Swedish forestry under a changing climate. Thus far, seed orchards with clones of phenotypically selected trees (plus trees) have been established to supply the market with highly qualitative reproductive material. Given the high genetic variation of the species, its growth properties are significantly affected by the provenance. Here, we applied microsatellite markers to identify the origin of clones selected within the Swedish breeding programme. Moreover, we analysed the timing of bud burst in open-pollinated families of these clones. In particular, we aimed to explain the provenance effect on phenology by using molecular identification as a proxy. A Bayesian clustering analysis with microsatellite data enabled the assignment of the clones to one of the two varieties and also resolved within-variety origins. The phenological observations indicated an earlier bud burst of the interior variety. Within the coastal variety, the northern provenances exhibited a later bud burst. We found a significant effect of the identified origin on bud burst timing. The results of this study will be used to support further breeding efforts.
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25.
  • Poetzelsberger, Elisabeth, et al. (författare)
  • Mapping the patchy legislative landscape of non-native tree species in Europe
  • 2020
  • Ingår i: Forestry (London). - : Oxford University Press. - 0015-752X .- 1464-3626. ; 93:4, s. 567-586
  • Tidskriftsartikel (refereegranskat)abstract
    • Europe has a history rich in examples of successful and problematic introductions of trees with a native origin outside of Europe (non-native trees, NNT). Many international legal frameworks such as treaties and conventions and also the European Union have responded to the global concern about potential negative impacts of NNT that may become invasive in natural ecosystems. It is, however, national and regional legislation in particular that affects current and future management decisions in the forest sector and shapes the landscapes of Europe. We identified all relevant legal instruments regulating NNT, the different legal approaches and the regulatory intensity in 40 European countries (no microstates). Information on hard and effective soft law instruments were collected by means of a targeted questionnaire and consultation of international and national legislation information systems and databases. In total, 335 relevant legal instruments were in place in June/July 2019 to regulate the use of NNT in the investigated 116 geopolitical legal units (countries as well as sub-national regions with their own legislation). Countries and regions were empirically categorized according to ad hoc-defined legislation indicators. These indicators pay respect to the general bans on the introduction of non-native species, the generally allowed and prohibited NNT, approval mechanisms and specific areas or cases where NNT are restricted or prohibited. Our study revealed a very diverse landscape of legal frameworks across Europe, with a large variety of approaches to regulating NNT being pursued and the intensity of restriction ranging from very few restrictions on species choice and plantation surface area to the complete banning of NNT from forests. The main conclusion is that there is a clear need for more co-ordinated, science-based policies both at the local and international levels to enhance the advantages of NNT and mitigate potential negative effects.
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