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Sökning: WFRF:(Ahlström A.)

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1.
  • Allentoft, M. E., et al. (författare)
  • Population genomics of Bronze Age Eurasia
  • 2015
  • Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 522:7555
  • Tidskriftsartikel (refereegranskat)abstract
    • The Bronze Age of Eurasia (around 3000-1000 BC) was a period of major cultural changes. However, there is debate about whether these changes resulted from the circulation of ideas or from human migrations, potentially also facilitating the spread of languages and certain phenotypic traits. We investigated this by using new, improved methods to sequence low-coverage genomes from 101 ancient humans from across Eurasia. We show that the Bronze Age was a highly dynamic period involving large-scale population migrations and replacements, responsible for shaping major parts of present-day demographic structure in both Europe and Asia. Our findings are consistent with the hypothesized spread of Indo-European languages during the Early Bronze Age. We also demonstrate that light skin pigmentation in Europeans was already present at high frequency in the Bronze Age, but not lactose tolerance, indicating a more recent onset of positive selection on lactose tolerance than previously thought.
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2.
  • Ahlström, A. P., et al. (författare)
  • Historically unprecedented global glacier decline in the early 21st century
  • 2015
  • Ingår i: Journal of Glaciology. - 0022-1430 .- 1727-5652. ; 61:228, s. 745-
  • Tidskriftsartikel (refereegranskat)abstract
    • Observations show that glaciers around the world are in retreat and losing mass. Internationally coordinated for over a century, glacier monitoring activities provide an unprecedented dataset of glacier observations from ground, air and space. Glacier studies generally select specific parts of these datasets to obtain optimal assessments of the mass-balance data relating to the impact that glaciers exercise on global sea-level fluctuations or on regional runoff. In this study we provide an overview and analysis of the main observational datasets compiled by the World Glacier Monitoring Service (WGMS). The dataset on glacier front variations (similar to 42 000 since 1600) delivers clear evidence that centennial glacier retreat is a global phenomenon. Intermittent readvance periods at regional and decadal scale are normally restricted to a subsample of glaciers and have not come close to achieving the maximum positions of the Little Ice Age (or Holocene). Glaciological and geodetic observations (similar to 5200 since 1850) show that the rates of early 21st-century mass loss are without precedent on a global scale, at least for the time period observed and probably also for recorded history, as indicated also in reconstructions from written and illustrated documents. This strong imbalance implies that glaciers in many regions will very likely suffer further ice loss, even if climate remains stable.
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3.
  • Wanhainen, Anders, et al. (författare)
  • The effect of ticagrelor on growth of small abdominal aortic aneurysms-a randomized controlled trial
  • 2020
  • Ingår i: Cardiovascular Research. - : Oxford University Press (OUP). - 0008-6363 .- 1755-3245. ; 116:2, s. 450-456
  • Tidskriftsartikel (refereegranskat)abstract
    • Aims: To evaluate if ticagrelor, an effective platelet inhibitor without known non-responders, could inhibit growth of small abdominal aortic aneurysms (AAAs). Methods and results: In this multi-centre randomized controlled trial, double-blinded for ticagrelor and placebo, acetylic salicylic acid naive patients with AAA and with a maximum aortic diameter 35-49mm were included. The primary outcome was mean reduction in log-transformed AAA volume growth rate (%) measured with magnetic resonance imaging (MRI) at 12months compared with baseline. Secondary outcomes include AAA-diameter growth rate and intraluminal thrombus (ILT) volume enlargement rate. A total of 144 patients from eight Swedish centres were randomized (72 in each group). MRI AAA volume increase was 9.1% for the ticagrelor group and 7.5% for the placebo group (P=0.205) based on intention-to-treat analysis, and 8.5% vs. 7.4% in a per-protocol analysis (P=0.372). MRI diameter change was 2.5mm vs. 1.8mm (P=0.113), US diameter change 2.3mm vs. 2.2mm (P=0.778), and ILT volume change 12.9% vs. 10.4% (P=0.590). Conclusion: In this RCT, platelet inhibition with ticagrelor did not reduce growth of small AAAs. Whether the ILT has an important pathophysiological role for AAA growth cannot be determined based on this study due to the observed lack of thrombus modulating effect of ticagrelor.
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4.
  • Fisher, J. B., et al. (författare)
  • Carbon cycle uncertainty in the Alaskan Arctic
  • 2014
  • Ingår i: Biogeosciences. - : Copernicus GmbH. - 1726-4189. ; 11:15, s. 4271-4288
  • Tidskriftsartikel (refereegranskat)abstract
    • Climate change is leading to a disproportionately large warming in the high northern latitudes, but the magnitude and sign of the future carbon balance of the Arctic are highly uncertain. Using 40 terrestrial biosphere models for the Alaskan Arctic from four recent model intercomparison projects - NACP (North American Carbon Program) site and regional syntheses, TRENDY (Trends in net land atmosphere carbon exchanges), and WETCHIMP (Wetland and Wetland CH4 Inter-comparison of Models Project) - we provide a baseline of terrestrial carbon cycle uncertainty, defined as the multi-model standard deviation (sigma) for each quantity that follows. Mean annual absolute uncertainty was largest for soil carbon (14.0+/-9.2 kgCm(-2)), then gross primary production (GPP) (0.22+/-0.50 kgCm(-2) yr(-1)), ecosystem respiration (Re) (0.23+/-0.38 kgCm(-2) yr(-1)), net primary production (NPP) (0.14+/-0.33 kgCm(-2) yr(-1)), autotrophic respiration (Ra) (0.09+/-0.20 kgCm(-2) yr(-1)), heterotrophic respiration (Rh) (0.14+/-0.20 kgCm(-2) yr(-1)), net ecosystem exchange (NEE) (-0.01+/-0.19 kgCm(-2) yr(-1)), and CH4 flux (2.52+/-4.02 g CH4 m(-2) yr(-1)). There were no consistent spatial patterns in the larger Alaskan Arctic and boreal regional carbon stocks and fluxes, with some models showing NEE for Alaska as a strong carbon sink, others as a strong carbon source, while still others as carbon neutral. Finally, AmeriFlux data are used at two sites in the Alaskan Arctic to evaluate the regional patterns; observed seasonal NEE was captured within multi-model uncertainty. This assessment of carbon cycle uncertainties may be used as a baseline for the improvement of experimental and modeling activities, as well as a reference for future trajectories in carbon cycling with climate change in the Alaskan Arctic and larger boreal region.
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5.
  • Luo, Yiqi, et al. (författare)
  • Toward more realistic projections of soil carbon dynamics by Earth system models
  • 2016
  • Ingår i: Global Biogeochemical Cycles. - 0886-6236. ; 30:1, s. 40-56
  • Tidskriftsartikel (refereegranskat)abstract
    • Soil carbon (C) is a critical component of Earth system models (ESMs), and its diverse representations are a major source of the large spread across models in the terrestrial C sink from the third to fifth assessment reports of the Intergovernmental Panel on Climate Change (IPCC). Improving soil C projections is of a high priority for Earth system modeling in the future IPCC and other assessments. To achieve this goal, we suggest that (1) model structures should reflect real-world processes, (2) parameters should be calibrated to match model outputs with observations, and (3) external forcing variables should accurately prescribe the environmental conditions that soils experience. First, most soil C cycle models simulate C input from litter production and C release through decomposition. The latter process has traditionally been represented by first-order decay functions, regulated primarily by temperature, moisture, litter quality, and soil texture. While this formulation well captures macroscopic soil organic C (SOC) dynamics, better understanding is needed of their underlying mechanisms as related to microbial processes, depth-dependent environmental controls, and other processes that strongly affect soil C dynamics. Second, incomplete use of observations in model parameterization is a major cause of bias in soil C projections from ESMs. Optimal parameter calibration with both pool- and flux-based data sets through data assimilation is among the highest priorities for near-term research to reduce biases among ESMs. Third, external variables are represented inconsistently among ESMs, leading to differences in modeled soil C dynamics. We recommend the implementation of traceability analyses to identify how external variables and model parameterizations influence SOC dynamics in different ESMs. Overall, projections of the terrestrial C sink can be substantially improved when reliable data sets are available to select the most representative model structure, constrain parameters, and prescribe forcing fields.
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6.
  • Pugh, T. A. M., et al. (författare)
  • Simulated carbon emissions from land-use change are substantially enhanced by accounting for agricultural management
  • 2015
  • Ingår i: Environmental Research Letters. - : IOP Publishing. - 1748-9326. ; 10:12
  • Tidskriftsartikel (refereegranskat)abstract
    • It is over three decades since a large terrestrial carbon sink (S-T) was first reported. The magnitude of the net sink is now relatively well known, and its importance for dampening atmospheric CO2 accumulation, and hence climate change, widely recognised. But the contributions of underlying processes are not well defined, particularly the role of emissions from land-use change (E-LUC) versus the biospheric carbon uptake (S-L; S-T. = S-L - E-LUC). One key aspect of the interplay of E-LUC and SL is the role of agricultural processes in land-use change emissions, which has not yet been clearly quantified at the global scale. Here we assess the effect of representing agricultural land management in a dynamic global vegetation model. Accounting for harvest, grazing and tillage resulted in cumulative E-LUC since 1850 ca. 70% larger than in simulations ignoring these processes, but also changed the timescale over which these emissions occurred and led to underestimations of the carbon sequestered by possible future reforestation actions. The vast majority of Earth system models in the recent IPCC Fifth Assessment Report omit these processes, suggesting either an overestimation in their present-day ST, or an underestimation of SL, of up to 1.0 Pg Ca-1. Management processes influencing crop productivity per se are important for food supply, but were found to have little influence on E-LUC.
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8.
  • Ahlström, Aisling, 1976, et al. (författare)
  • A double-blind randomized controlled trial investigating a time-lapse algorithm for selecting Day 5 blastocysts for transfer
  • 2022
  • Ingår i: Human Reproduction. - : Oxford University Press (OUP). - 0268-1161 .- 1460-2350. ; 37:4, s. 708-717
  • Tidskriftsartikel (refereegranskat)abstract
    • STUDY QUESTION Can use of a commercially available time-lapse algorithm for Day 5 blastocyst selection improve pregnancy rates compared with morphology alone? SUMMARY ANSWER The use of a time-lapse selection model to choose blastocysts for fresh single embryo transfer on Day 5 did not improve ongoing pregnancy rate compared to morphology alone. WHAT IS KNOWN ALREADY Evidence from time-lapse monitoring suggests correlations between timing of key developmental events and embryo viability. No good quality evidence exists to support improved pregnancy rates following time-lapse selection. STUDY DESIGN, SIZE, DURATION A prospective multicenter randomized controlled trial including 776 randomized patients was performed between 2018 and 2021. Patients with at least two good quality blastocysts on Day 5 were allocated by a computer randomization program in a proportion of 1:1 into either the control group, whereby single blastocysts were selected for transfer by morphology alone, or the intervention group whereby final selection was decided by a commercially available time-lapse model. The embryologists at the time of blastocyst morphological scoring were blinded to which study group the patients would be randomized, and the physician and patients were blind to which group they were allocated until after the primary outcome was known. The primary outcome was number of ongoing pregnancies in the two groups. PARTICIPANTS/MATERIALS, SETTING, METHODS From 10 Nordic IVF clinics, 776 patients with a minimum of two good quality blastocysts on Day 5 (D5) were randomized into one of the two study groups. A commercial time-lapse model decided the final selection of blastocysts for 387 patients in the intervention (time-lapse) group, and blastocysts with the highest morphological score were transferred for 389 patients in the control group. Only single embryo transfers in fresh cycles were performed. MAIN RESULTS AND THE ROLE OF CHANCE In the full analysis set, the ongoing pregnancy rate for the time-lapse group was 47.4% (175/369) and 48.1% (181/376) in the control group. No statistically significant difference was found between the two groups: mean difference -0.7% (95% CI -8.2, 6.7, P = 0.90). Pregnancy rate (60.2% versus 59.0%, mean difference 1.1%, 95% CI -6.2, 8.4, P = 0.81) and early pregnancy loss (21.2% versus 18.5%, mean difference 2.7%, 95% CI -5.2, 10.6, P = 0.55) were the same for the time-lapse and the control group. Subgroup analyses showed that patient and treatment characteristics did not significantly affect the commercial time-lapse model D5 performance. In the time-lapse group, the choice of best blastocyst changed on 42% of occasions (154/369, 95% CI 36.9, 47.2) after the algorithm was applied, and this rate was similar for most treatment clinics. LIMITATIONS, REASONS FOR CAUTION During 2020, the patient recruitment rate slowed down at participating clinics owing to coronavirus disease-19 restrictions, so the target sample size was not achieved as planned and it was decided to stop the trial prematurely. The study only investigated embryo selection at the blastocyst stage on D5 in fresh IVF transfer cycles. In addition, only blastocysts of good morphological quality were considered for transfer, limiting the number of embryos for selection in both groups: also, it could be argued that this manual preselection of blastocysts limits the theoretical selection power of time-lapse, as well as restricting the results mainly to a good prognosis patient group. Most patients were aimed for blastocyst stage transfer when a minimum of five zygotes were available for extended culture. Finally, the primary clinical outcome evaluated was pregnancy to only 6-8 weeks. WIDER IMPLICATIONS OF THE FINDINGS The study suggests that time-lapse selection with a commercially available time-lapse model does not increase chance of ongoing pregnancy after single blastocyst transfer on Day 5 compared to morphology alone. STUDY FUNDING/COMPETING INTEREST(S) The study was financed by a grant from the Swedish state under the ALF-agreement between the Swedish government and the county councils (ALFGBG-723141). Vitrolife supported the study with embryo culture dishes and culture media. During the study period, T.H. changed his employment from Livio AB to Vitrolife AB. All other authors have no conflicts of interests to disclose. DATE OF FIRST PATIENT'S ENROLMENT 11 June 2018.
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9.
  • Ahlström, A., et al. (författare)
  • No major differences in perinatal and maternal outcomes between uninterrupted embryo culture in time-lapse system and conventional embryo culture
  • 2023
  • Ingår i: Human Reproduction. - : Oxford University Press. - 0268-1161 .- 1460-2350. ; 38:12, s. 2400-2411
  • Tidskriftsartikel (refereegranskat)abstract
    • STUDY QUESTION: Is embryo culture in a closed time-lapse system associated with any differences in perinatal and maternal outcomes in comparison to conventional culture and spontaneous conception?SUMMARY ANSWER: There were no significant differences between time-lapse and conventional embryo culture in preterm birth (PTB, <37 weeks), low birth weight (LBW, >2500 g) and hypertensive disorders of pregnancy for singleton deliveries, the primary outcomes of this study.WHAT IS KNOWN ALREADY: Evidence from prospective trials evaluating the safety of time-lapse incubation for clinical use show similar embryo development rates, implantation rates, and ongoing pregnancy and live birth rates when compared to conventional incubation. Few studies have investigated if uninterrupted culture can alter risks of adverse perinatal outcomes presently associated with IVF when compared to conventional culture and spontaneous conceptions.STUDY DESIGN, SIZE, DURATION: This study is a Swedish population-based retrospective registry study, including 7379 singleton deliveries after fresh embryo transfer between 2013 and 2018 from selected IVF clinics. Perinatal outcomes of singletons born from time-lapse-cultured embryos were compared to singletons from embryos cultured in conventional incubators and 71 300 singletons from spontaneous conceptions. Main perinatal outcomes included PTB and LBW. Main maternal outcomes included hypertensive disorders of pregnancy (pregnancy hypertension and preeclampsia).PARTICIPANTS/MATERIALS, SETTING, METHODS: From nine IVF clinics, 2683 singletons born after fresh embryo transfer in a time-lapse system were compared to 4696 singletons born after culture in a conventional incubator and 71 300 singletons born after spontaneous conception matched for year of birth, parity, and maternal age. Patient and treatment characteristics from IVF deliveries were cross-linked with the Swedish Medical Birth Register, Register of Birth Defects, National Patient Register and Statistics Sweden. Children born after sperm and oocyte donation cycles and after Preimplantation Genetic testing cycles were excluded. Odds ratio (OR) and adjusted OR were calculated, adjusting for relevant confounders.MAIN RESULTS AND THE ROLE OF CHANCE: In the adjusted analyses, no significant differences were found for risk of PTB (adjusted OR 1.11, 95% CI 0.87-1.41) and LBW (adjusted OR 0.86, 95% CI 0.66-1.14) or hypertensive disorders of pregnancy; preeclampsia and hypertension (adjusted OR 0.99, 95% CI 0.67-1.45 and adjusted OR 0.98, 95% CI 0.62-1.53, respectively) between time-lapse and conventional incubation systems. A significantly increased risk of PTB (adjusted OR 1.31, 95% CI 1.08-1.60) and LBW (adjusted OR 1.36, 95% CI 1.08-1.72) was found for singletons born after time-lapse incubation compared to singletons born after spontaneous conceptions. In addition, a lower risk for pregnancy hypertension (adjusted OR 0.72 95% CI 0.53-0.99) but no significant difference for preeclampsia (adjusted OR 0.87, 95% CI 0.68-1.12) was found compared to spontaneous conceptions. Subgroup analyses showed that some risks were related to the day of embryo transfer, with more adverse outcomes after blastocyst transfer in comparison to cleavage stage transfer.LIMITATIONS, REASONS FOR CAUTION: This study is retrospective in design and different clinical strategies may have been used to select specific patient groups for time-lapse versus conventional incubation. The number of patients is limited and larger datasets are required to obtain more precise estimates and adjust for possible effect of additional embryo culture variables.WIDER IMPLICATIONS OF THE FINDINGS: Embryo culture in time-lapse systems is not associated with major differences in perinatal and maternal outcomes, compared to conventional embryo culture, suggesting that this technology is an acceptable alternative for embryo incubation.
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10.
  • Ahlström, Håkan, et al. (författare)
  • Pulmonary MR angiography with ultrasmall superparamagnetic iron oxide particles as a blood pool agent and a navigator echo for respiratory gating : pilot study
  • 1999
  • Ingår i: Radiology. - 0033-8419 .- 1527-1315. ; 211:3, s. 865-869
  • Tidskriftsartikel (refereegranskat)abstract
    • In nine healthy adult volunteers, pulmonary magnetic resonance angiography was performed with the blood pool agent NC100150 injection combined with respiratory gating with a navigator echo. With increasing doses of the contrast agent, higher signal intensities and vessel branch order visualization were achieved. No motion artifacts were seen. The blood pool agent NC100150 injection in combination with respiratory navigator gating permitted acquisition of high-quality MR angiograms of the pulmonary vasculature during continuous breathing.
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13.
  • Garcia-Larsen, V., et al. (författare)
  • Dietary intake of flavonoids and ventilatory function in european adults: A GA2LEN study
  • 2018
  • Ingår i: Nutrients. - Basel : MDPI AG. - 2072-6643. ; 10:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Flavonoids exert anti-inflammatory properties and modulate oxidative stress in vitro, suggesting a protective effect on lung function, but epidemiological studies examining this association are scarce. Methods: A stratified random sample was drawn from the GA2LEN screening survey, in which 55,000 adults aged 15 to 75 answered a questionnaire on respiratory symptoms. Post-bronchodilator spirometry was obtained from 2850 subjects. Forced vital capacity (FVC), the ratio between the forced exhaled volume in 1 second (FEV1) and FVC (FEV1/FVC), FVC below lower limit of normal (FVC < LLN), and FEV1/FVC < LLN were calculated. Intake of the six main subclasses of flavonoids was estimated using the GA2LEN Food Frequency Questionnaire. Adjusted associations between outcomes and each subclass of flavonoids were examined with multivariate regressions. Simes’ procedure was used to test for multiple comparisons. Results: A total of 2599 subjects had valid lung function and dietary data. A lower prevalence of FVC < LLN (airway restriction) was observed in those with higher total flavonoid (adjusted odds ratio (aOR), higher vs. lowest quintile intake 0.58, 95% Confidence Interval (CI) 0.36, 0.94), and pro-anthocyanidin intakes (aOR 0.47, 95% CI 0.27, 0.81). A higher FEV1/FVC was associated with higher intakes of total flavonoids and pro-anthocyanidins (adjusted correlation coefficient (a β-coeff 0.33, 0.10, 0.57 and a β-coeff 0.44, 95% CI 0.19, 0.69, respectively). After Simes’ procedure, the statistical significance of each of these associations was attenuated but remained below 0.05, with the exception of total flavonoids and airway restriction. Conclusions: This population-based study in European adults provides cross-sectional evidence of a positive association of total flavonoid intake and pro-anthocyanidins and ventilatory function, and a negative association with spirometric restriction in European adults. © 2018 by the authors. Licensee MDPI, Basel, Switzerland.
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14.
  • Jacobsson, Josefin A., et al. (författare)
  • Detailed Analysis of Variants in FTO in Association with Body Composition in a Cohort of 70-Year-Olds Suggests a Weakened Effect among Elderly
  • 2011
  • Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 6:5, s. e20158-
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: The rs9939609 single-nucleotide polymorphism (SNP) in the fat mass and obesity (FTO) gene has previously been associated with higher BMI levels in children and young adults. In contrast, this association was not found in elderly men. BMI is a measure of overweight in relation to the individuals' height, but offers no insight into the regional body fat composition or distribution. Objective: To examine whether the FTO gene is associated with overweight and body composition-related phenotypes rather than BMI, we measured waist circumference, total fat mass, trunk fat mass, leg fat mass, visceral and subcutaneous adipose tissue, and daily energy intake in 985 humans (493 women) at the age of 70 years. In total, 733 SNPs located in the FTO gene were genotyped in order to examine whether rs9939609 alone or the other SNPs, or their combinations, are linked to obesity-related measures in elderly humans. Design: Cross-sectional analysis of the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) cohort. Results: Neither a single SNP, such as rs9939609, nor a SNP combination was significantly linked to overweight, body composition-related measures, or daily energy intake in elderly humans. Of note, these observations hold both among men and women. Conclusions: Due to the diversity of measurements included in the study, our findings strengthen the view that the effect of FTO on body composition appears to be less profound in later life compared to younger ages and that this is seemingly independent of gender.
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15.
  • Johansson, A. Malin (författare)
  • Remote sensing of supra-glacial lakes on the west Greenland Ice Sheet
  • 2012
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • The Greenland Ice Sheet is the largest ice sheet in the northern hemisphere. Ongoing melting of the ice sheet, resulting in increased mass loss relative to the longer term trend, has raised concerns about the stability of the ice sheet. Melt water generated at the surface is temporarily stored in supra-glacial lakes on the ice sheet. Connections between melt water generation, storage and ice sheet dynamics highlight the importance of the surface hydrological system.In this thesis different methods are used that improve our ability to observe the supra-glacial lake system on the west Greenland Ice Sheet. This region of the Greenland Ice Sheet has the most extensive supra-glacial hydrological system with a dense network of streams connecting lakes that can exceed several square kilometres in area. Synthetic Aperture Radar (SAR) and visible-near infrared (VNIR) images are used to explore the potential of different sensor systems for regular observations of the supra-glacial lakes. SAR imagery is found to be a useful complement to VNIR data. VNIR data from moderate resolution sensors are preferred as these provide high temporal resolution data, ameliorating problems with cloud cover.The dynamic nature of the lakes makes automated classification difficult and manual mapping has been widely used. Here a new method is proposed that improves on existing methods by automating the identification and classification of lakes, and by introducing a flexible system that can capture the full range of lake forms. Applying our new method we are better able to analyse the evolution of lakes over a number of melt seasons. We find that lakes initiate after approximately 40 positive degree days. Most lakes exist for less than 20 days before draining, or later in the season, and less often, freezing over. Using the automated method developed in this thesis lakes have been mapped in imagery from 2001–2010 at approximately five day intervals.
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16.
  • Metcalfe, Daniel B., et al. (författare)
  • Patchy field sampling biases understanding of climate change impacts across the Arctic
  • 2018
  • Ingår i: Nature Ecology and Evolution. - : Springer Science and Business Media LLC. - 2397-334X. ; 2:9, s. 1443-1448
  • Tidskriftsartikel (refereegranskat)abstract
    • Effective societal responses to rapid climate change in the Arctic rely on an accurate representation of region-specific ecosystem properties and processes. However, this is limited by the scarcity and patchy distribution of field measurements. Here, we use a comprehensive, geo-referenced database of primary field measurements in 1,840 published studies across the Arctic to identify statistically significant spatial biases in field sampling and study citation across this globally important region. We find that 31% of all study citations are derived from sites located within 50 km of just two research sites: Toolik Lake in the USA and Abisko in Sweden. Furthermore, relatively colder, more rapidly warming and sparsely vegetated sites are under-sampled and under-recognized in terms of citations, particularly among microbiology-related studies. The poorly sampled and cited areas, mainly in the Canadian high-Arctic archipelago and the Arctic coastline of Russia, constitute a large fraction of the Arctic ice-free land area. Our results suggest that the current pattern of sampling and citation may bias the scientific consensuses that underpin attempts to accurately predict and effectively mitigate climate change in the region. Further work is required to increase both the quality and quantity of sampling, and incorporate existing literature from poorly cited areas to generate a more representative picture of Arctic climate change and its environmental impacts.
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17.
  • Nelson, A E, et al. (författare)
  • Diagnosis of a patient with oncogenic osteomalacia using a phosphate uptake bioassay of serum and magnetic resonance imaging
  • 2001
  • Ingår i: European Journal of Endocrinology. - : Oxford University Press (OUP). - 0804-4643 .- 1479-683X. ; 145:4, s. 469-476
  • Tidskriftsartikel (refereegranskat)abstract
    • A previously healthy man with no family history of fractures presented with muscle pain, back pain and height loss. Investigations revealed hypophosphataemia, phosphaturia, undetectable serum 1,25-dihydroxyvitamin D and severe osteomalacia on bone biopsy, suggestive of a diagnosis of oncogenic osteomalacia. Thorough physical examination did not locate a tumour. Support for the diagnosis was obtained by detection of phosphate uptake inhibitory activity in a blinded sample of the patient's serum using a renal cell bioassay. On the basis of detection of this bioactivity, a total body magnetic resonance (MR) examination was performed. A small tumour was located in the right leg. Removal of the tumour resulted in the rapid reversal of symptoms and the abnormal biochemistry typical of oncogenic osteomalacia. Inhibitory activity was also demonstrated using the bioassay in serum from two other patients with confirmed or presumptive oncogenic osteomalacia, but not in serum from two patients with hypophosphataemia of other origin. This is the first case to be reported in which the diagnosis of oncogenic osteomalacia was assisted by demonstration of inhibitory activity of the patient's serum in a renal cell phosphate bioassay that provided an impetus for total body MR imaging.
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18.
  • Pellegrini, Adam F.A., et al. (författare)
  • Fire frequency drives decadal changes in soil carbon and nitrogen and ecosystem productivity
  • 2018
  • Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 553:7687, s. 194-198
  • Tidskriftsartikel (refereegranskat)abstract
    • Fire frequency is changing globally and is projected to affect the global carbon cycle and climate. However, uncertainty about how ecosystems respond to decadal changes in fire frequency makes it difficult to predict the effects of altered fire regimes on the carbon cycle; for instance, we do not fully understand the long-term effects of fire on soil carbon and nutrient storage, or whether fire-driven nutrient losses limit plant productivity. Here we analyse data from 48 sites in savanna grasslands, broadleaf forests and needleleaf forests spanning up to 65 years, during which time the frequency of fires was altered at each site. We find that frequently burned plots experienced a decline in surface soil carbon and nitrogen that was non-saturating through time, having 36 per cent (±13 per cent) less carbon and 38 per cent (±16 per cent) less nitrogen after 64 years than plots that were protected from fire. Fire-driven carbon and nitrogen losses were substantial in savanna grasslands and broadleaf forests, but not in temperate and boreal needleleaf forests. We also observe comparable soil carbon and nitrogen losses in an independent field dataset and in dynamic model simulations of global vegetation. The model study predicts that the long-term losses of soil nitrogen that result from more frequent burning may in turn decrease the carbon that is sequestered by net primary productivity by about 20 per cent of the total carbon that is emitted from burning biomass over the same period. Furthermore, we estimate that the effects of changes in fire frequency on ecosystem carbon storage may be 30 per cent too low if they do not include multidecadal changes in soil carbon, especially in drier savanna grasslands. Future changes in fire frequency may shift ecosystem carbon storage by changing soil carbon pools and nitrogen limitations on plant growth, altering the carbon sink capacity of frequently burning savanna grasslands and broadleaf forests.
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19.
  • Piao, S. L., et al. (författare)
  • The carbon budget of terrestrial ecosystems in East Asia over the last two decades
  • 2012
  • Ingår i: Biogeosciences. - : Copernicus GmbH. - 1726-4189. ; 9:9, s. 3571-3586
  • Tidskriftsartikel (refereegranskat)abstract
    • This REgional Carbon Cycle Assessment and Processes regional study provides a synthesis of the carbon balance of terrestrial ecosystems in East Asia, a region comprised of China, Japan, North and South Korea, and Mongolia. We estimate the current terrestrial carbon balance of East Asia and its driving mechanisms during 1990-2009 using three different approaches: inventories combined with satellite greenness measurements, terrestrial ecosystem carbon cycle models and atmospheric inversion models. The magnitudes of East Asia's terrestrial carbon sink from these three approaches are comparable: -0.293 +/- 0.033 PgC yr(-1) from inventory-remote sensing model-data fusion approach, -0.413 +/- 0.141 PgC yr(-1)(not considering biofuel emissions) or -0.224 +/- 0.141 PgC yr(-1) (considering biofuel emissions) for carbon cycle models, and -0.270 +/- 0.507 PgC yr(-1) for atmospheric inverse models. Here and in the following, the numbers behind +/- signs are standard deviations. The ensemble of ecosystem modeling based analyses further suggests that at the regional scale, climate change and rising atmospheric CO2 together resulted in a carbon sink of -0.289 +/- 0.135 PgC yr(-1), while land-use change and nitrogen deposition had a contribution of -0.013 +/- 0.029 PgC yr(-1) and -0.107 +/- 0.025 PgC yr(-1), respectively. Although the magnitude of climate change effects on the carbon balance varies among different models, all models agree that in response to climate change alone, southern China experienced an increase in carbon storage from 1990 to 2009, while northern East Asia including Mongolia and north China showed a decrease in carbon storage. Overall, our results suggest that about 13-27% of East Asia's CO2 emissions from fossil fuel burning have been offset by carbon accumulation in its terrestrial territory over the period from 1990 to 2009. The underlying mechanisms of carbon sink over East Asia still remain largely uncertain, given the diversity and intensity of land management processes, and the regional conjunction of many drivers such as nutrient deposition, climate, atmospheric pollution and CO2 changes, which cannot be considered as independent for their effects on carbon storage.
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20.
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21.
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22.
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23.
  • Ahlström, Anders, et al. (författare)
  • Hydrologic resilience and Amazon productivity
  • 2017
  • Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 8:1
  • Tidskriftsartikel (refereegranskat)abstract
    • The Amazon rainforest is disproportionately important for global carbon storage and biodiversity. The system couples the atmosphere and land, with moist forest that depends on convection to sustain gross primary productivity and growth. Earth system models that estimate future climate and vegetation show little agreement in Amazon simulations. Here we show that biases in internally generated climate, primarily precipitation, explain most of the uncertainty in Earth system model results; models, empirical data and theory converge when precipitation biases are accounted for. Gross primary productivity, above-ground biomass and tree cover align on a hydrological relationship with a breakpoint at ~2000 mm annual precipitation, where the system transitions between water and radiation limitation of evapotranspiration. The breakpoint appears to be fairly stable in the future, suggesting resilience of the Amazon to climate change. Changes in precipitation and land use are therefore more likely to govern biomass and vegetation structure in Amazonia.
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24.
  • Ahlström-Emanuelsson, Cecilia, et al. (författare)
  • Establishing a model of seasonal allergic rhinitis and demonstrating dose-response to a topical glucocorticosteroid
  • 2002
  • Ingår i: Annals of Allergy, Asthma & Immunology. - 1081-1206. ; 89:2, s. 159-165
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Symptoms of seasonal allergic rhinitis may vary greatly. Hence, for research purposes, there is a need for disease-like models of allergic rhinitis. In a preliminary study, involving 7 days' challenge with allergen, promising symptom consistency was obtained and dose-response to a glucocorticosteroid could, in part, be demonstrated. Objective: To establish this model of seasonal allergic rhinitis and test the hypothesis that mometasone furoate is more potent than budesonide as an antirhinitis drug. Methods: Thirty-eight patients with seasonal allergic rhinitis received treatment with spray-formulations of placebo, budesonide 64 kg, budesonide 256 mug, and mometasone furoate 200 mug in a double-blind, crossover design. After 3 days' treatment, individualized nasal allergen-challenges were administered daily for 7 days while the treatment continued. Nasal symptoms and peak inspiratory flow (PIF) were recorded. Results: During the last 3 days of allergen challenge without active treatment, consistent around-the-clock symptoms were recorded and recordings during these days were used in the analysis. With few exceptions the active treatments reduced nasal symptoms and improved nasal PIF (P values <0.001 to 0.05). Budesonide caused dose-dependent improvements in evening symptoms, morning nasal PIF, and nasal PIF recorded 10 minutes after allergen-challenge (P values <0.05). Budesonide 256 mug produced greater improvement than mometasone furoate 200 mug for nasal PIF 10 minutes after allergen-challenge (P < 0.05). Conclusion: The present allergen challenge method, producing consistent symptoms and nasal PIF data, emerges as a model of seasonal allergic rhinitis well suited for exploring potency and efficacy of drug intervention. The present data do not support the view that mometasone furoate is a more potent antirhinitis drug than budesonide.
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25.
  • Ahlström, G., et al. (författare)
  • Health care utilisation among older people with Down syndrome compared to specific medical guidelines for health surveillance : a Swedish national register study
  • 2020
  • Ingår i: BMC Health Services Research. - : Springer Science and Business Media LLC. - 1472-6963. ; 20:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Specific medical guidelines for health surveillance exist for people with Down syndrome (DS) since 25 years but knowledge of adherence to the guidelines is lacking. The guidelines were developed to avoid unnecessary suffering from preventable conditions. The aims of the study were to investigate 1) planned health care visits in relation to the co-morbidities described in specific medical guidelines as a measure of adherence, 2) unplanned health care visits as a measure of potentially unmet health care needs and 3) gender differences in health care utilisation among older people with DS. Methods: This register-based study includes people with DS (n = 472) from a Swedish national cohort of people with intellectual disability (n = 7936), aged 55 years or more, and with at least one support according to the disability law, in 2012. Data on inpatient and outpatient specialist health care utilisation were collected from the National Patient Register for 2002–2012. Results: A total of 3854 inpatient and outpatient specialist health care visits were recorded during the 11 years, of which 54.6% (n = 2103) were planned, 44.0% (n = 1695) unplanned and 1.4% (n = 56) lacked information. More than half of the visits, 67.0% (n = 2582) were outpatient health care thus inpatient 33% (n = 1272). Most planned visits (29.4%, n = 618) were to an ophthalmology clinic, and most unplanned visits to an internal medicine clinic (36.6%, n = 621). The most common cause for planned visits was cataract, found at least once for 32.8% in this cohort, followed by arthrosis (8.9%), epilepsy (8.9%) and dementia (6.6%). Pneumonia, pain, fractures and epilepsy each accounted for at least one unplanned visit for approximately one-fourth of the population (27.1, 26.9, 26.3 and 19.7% respectively). Men and women had similar numbers of unplanned visits. However, women were more likely to have visits for epilepsy or fractures, and men more likely for pneumonia. Conclusions: Increased awareness of existing specific medical guidelines for people with DS is vital for preventive measures. The relatively few planned health care visits according to the medical guidelines together with a high number of unplanned visits caused by conditions which potentially can be prevented suggest a need of improved adherence to medical guidelines.
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26.
  • Ahlström, G, et al. (författare)
  • Specialist psychiatric health care utilization among older people with intellectual disability - predictors and comparisons with the general population : a national register study
  • 2020
  • Ingår i: BMC Psychiatry. - : Springer Science and Business Media LLC. - 1471-244X. ; 20
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND: People with intellectual disability (ID) face considerable barriers to accessing psychiatric health care, thus there is a risk for health disparity. The aims of the present study were 1) to compare specialist psychiatric health care utilization among older people with ID to that with their age peers in the general population, taking into account demographic factors and co-morbidities associated with specialist psychiatric health care utilization and 2) to determine a model for prediction of specialist psychiatric health care utilization among older people with ID.MATERIAL AND METHODS: We identified a national cohort of people with ID (ID cohort), aged 55+ years and alive at the end of 2012 (n = 7936), and a referent cohort from the general population (gPop cohort) one-to-one matched by year of birth and sex. Data on utilization of inpatient and outpatient specialist psychiatric health care, as well as on co-morbidities identified in either psychiatric or somatic specialist health care, were collected from the National Patient Register for the time period 2002-2012.RESULTS: After adjusting for sex, age, specialist psychiatric health care utilization the previous year, and co-morbidities, people in the ID cohort still had an increased risk of visits to unplanned inpatient (relative risk [RR] 1.95), unplanned outpatient (RR 1.59), planned inpatient (RR 2.02), and planned outpatient (RR 1.93) specialist psychiatric health care compared with the general population. Within the ID cohort, increasing age was a predictor for less health care, whereas psychiatric health care the previous year predicted increased risk of health care utilization the current year. As expected, mental and behavioral disorders predicted increased risk for psychiatric health care. Furthermore, episodic and paroxysmal disorders increased the risk of planned psychiatric health care.CONCLUSIONS: Older people with ID have a high need for psychiatric specialist health care due to a complex pattern of diagnoses. Further research needs to investigate the conditions that can explain the lesser psychiatric care in higher age groups. There is also a need of research on health care utilization among people with ID in the primary health care context. This knowledge is critical for policymakers' plans of resources to meet the needs of these people.
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27.
  • Ahlström, Håkan, et al. (författare)
  • An experimental model for pharmacokinetic studies of monoclonal antibodies in human colonic cancer
  • 1987
  • Ingår i: Acta Oncologica. - 0284-186X .- 1651-226X. ; 26:6, s. 447-451
  • Tidskriftsartikel (refereegranskat)abstract
    • An experimental model consisting of athymic rats carrying human colonic tumours from cell line LS 174T in both hind legs was used. 125I-labelled anti-carcinoembryonic antigen (anti-CEA) monoclonal antibodies were injected intra-arterially (i.a.), either alone (21 rats) or together with degradable starch microspheres (6 rats). As a control, an irrelevant antibody was injected i.a., alone (6 rats) or together with microspheres (3 rats). An intra-arterial injection was given on the side bearing one tumour in each rat, while the contralateral tumour served as an 'intravenous' control. The rats were submitted to external gamma measurements daily for four days. On the fourth day they were killed and pieces from the tumours and from various organs were examined by in vitro measurements. The results indicate strong expression of CEA in LS 174T cells grafted to athymic rats. No lasting enhancement of the tumour uptake was achieved by intra-arterial injection of antibodies as compared with the control tumours.
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28.
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29.
  • Ahlström, Håkan, et al. (författare)
  • Enhanced uptake of intra-arterially injected anti-CEA monoclonal antibodies in human colonic cancer after mannitol infusion in an experimental model
  • 1987
  • Ingår i: Acta Oncologica. - 0284-186X .- 1651-226X. ; 26:6, s. 453-458
  • Tidskriftsartikel (refereegranskat)abstract
    • In a previous report athymic rats carrying transplanted human colonic tumours from cell line LS 174T in both hind legs were injected intra-arterially (i.a.) with 125I-labelled anti-carcinoembryonic (anti-CEA) monoclonal antibodies. The i.a. injection was given on one side bearing a tumour in each rat, while the contralateral tumour served as an 'intravenous' control. In the same experimental model and treated in the same way, 10 rats were injected i.a. with anti-CEA monoclonal antibodies after an i.a. mannitol infusion. In both groups of rats external gamma measurements were performed daily for four days. On the fourth day the rats were killed and pieces of the tumours and of various organs were weighed and the activity was determined with a gamma-counter. The tumour uptake of antibodies was significantly enhanced after mannitol infusion.
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30.
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31.
  • Ahlström, Håkan, et al. (författare)
  • The spatial distribution of parenterally administered monoclonal antibodies against CEA in a human colorectal tumour xenograft
  • 1989
  • Ingår i: Acta Oncologica. - 0284-186X .- 1651-226X. ; 28:1, s. 81-86
  • Tidskriftsartikel (refereegranskat)abstract
    • A recently developed experimental model consisting of athymic rats carrying human colonic tumours from the cell line LS 174 T in both hind legs was used. 125I-labelled anti-carcinoembryonic (anti-CEA) monoclonal antibodies were injected either intra-arterially after a bolus injection of mannitol, or intra-peritoneally with or without mannitol. On the fourth day the rats were killed and pieces from the tumours and various organs were measured in a well scintillation counter. Tumour pieces were then submitted to autoradiography and immunohistochemistry for examination of the antibody distribution at the cellular level. In all examined tumours injected with anti-CEA antibodies, most of the antibodies were located in the periphery close to fibrovascular septa. It appears, in addition to the specificity of the antibody for the CEA, that the tumour vascular permeability and anatomy are of utmost importance for tumour targeting in this experimental model with the particular antibody used.
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32.
  • Ahlström, Peter, et al. (författare)
  • A Survey of the Role of Thermodynamics and Transport Properties in ChE University Education in Europe and the USA
  • 2010
  • Ingår i: Chemical Engineering Education. - : Chemical Engineering Department, University of Florida. - 0009-2479. ; 44:1, s. 35-43
  • Tidskriftsartikel (refereegranskat)abstract
    • Thermodynamics and Transport Properties (TTP) is a central subject in the majority of chemical engineering curricula worldwide and it is thus of interest to know how it is taught today in various countries if chemical engineering education is to be improved. A survey of graduate thermodynamics education in the USA was performed a few years ago by Visco et al. [1] but as far as we know no systematic study of the undergraduate thermodynamics education has been performed, at least in recent years. In the present study, a survey about TTP education in Europe and the USA is presented. Results were obtained from nearly twenty different European countries and the USA and in total answers from about 150 universities were used for this study. The study is performed under the auspices of the Working Party of Thermodynamics and Transport Properties of the European Federation of Chemical Engineering. The survey was performed using a web based surveying system for which invitations were sent out to the universities by local representatives who were responsible for one or more countries each. Of the universities that answered more than 70 % offer BSc education 65 % offer MSc education and 55 % offer PhD education. Most universities offer at least two courses of thermodynamics. The following discussion is mainly based on the first two (undergraduate) courses reported. Half of these are taught to chemical engineers exclusively whereas the rest are taught with other branches of engineering, mainly mechanical and / or process engineering. In general two sets of course lengths were observed, corresponding either to a full semester of full time studies or to quarter of a semester. Most courses are centered around lectures and exercise classes with little or no laboratory work whereas home assignments are given in the vast majority (70-80 %) of the courses. The first course is mainly centered around the first and second law of thermodynamics whereas the second course is frequently more concentrated on phase equilibria. Both of these courses are mainly comprising of classical thermodynamics whereas the molecular interpretation often is touched upon. An analysis of the differences between thermodynamics education in Europe and the USA in presently being undertaken and results from this will also be presented. An investigation of the use of thermodynamics within industry is also on-going within the Working Party and results will be reported in the near future. [1] S.K.Dube, D.P. Visco, Chem. Eng. Ed., 2005, 258-263.
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33.
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34.
  • Ahlström, Torbjörn, et al. (författare)
  • Swedish paleopathology and its pioneers
  • 2012
  • Ingår i: The global history of paleopathology : Pioneers and prospects - Pioneers and prospects. - : Oxford University Press. - 9780195389807 ; , s. 549-558
  • Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
    • This chapter discusses the history of paleopathology in Sweden. Paleopathology of skeletal remains in Sweden is considered a subfield of historical osteology, a discipline that combines the study of human and animal bones from archaeological sites, with roots in the works of Nils-Gustaf Gejvall (1911–1991). The chapter describes the development of the field from its beginnings in paleopathological work carried out on a personal interest basis to its establishment as an academic discipline. It identifies three pioneers—Carl Magnus Fürst (1854–1935), Carl-Herman Hjortsjö, and Gejvall—whose contributions are directly linked to the establishment of historical osteology.
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35.
  • Axmon, A., et al. (författare)
  • Drug use and healthcare consumption among persons with intellectual disabilities and dementia: A registry study
  • 2016
  • Ingår i: Journal of Intellectual Disability Research. - : Wiley. - 0964-2633. ; 60:7-8, s. 632-632
  • Konferensbidrag (refereegranskat)abstract
    • Aim: To describe drug use and healthcare utilisation among persons with intellectual disabilities (ID) and dementia in comparison to persons with ID only and dementia only. Method: From the group of persons with ID (n=7936), 216 individuals with dementia were identified. 81 persons with dementia were identified from a general population sample matched by age and sex. Information on outcomes was collected retrospectively from national registries. Healthcare utilisation was measured as the number of hospital visits and the number of hospitalisations. Drug use was assessed for antipsychotics, benzodiazepine derivatives, and anticholinesterases. Results: Persons with ID and dementia had higher healthcare utilisation than persons with ID but without dementia, but similar levels as persons with dementia in the general population sample. They were more likely to use antipsychotics and less likely to use anticholinesterases than persons with dementia but without ID. Conclusions: Dementia in persons with ID seems to increase healthcare utilisation and drug use. However, with respect to healthcare utilisation, the levels do not exceed those found among persons with dementia in the general population.
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36.
  • Axmon, A, et al. (författare)
  • Falls resulting in health care among older people with intellectual disability in comparison with the general population
  • 2019
  • Ingår i: Journal of Intellectual Disability Research. - : Wiley. - 0964-2633. ; 63:3, s. 193-204
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND: Falls are common among older people with intellectual disability (ID) and are also a major contributor to injuries in this population. Yet, fall characteristics have only been sparsely studied, and the results are inconsistent. The aim of the present study was to investigate type of falls, places where they occurred and activities that caused them, as well as health outcomes and health utilisation patterns after falls, among older people with ID in comparison with their age peers in the general population.METHODS: We established an administrative cohort of people with ID aged 55 years, or more, and alive at the end of 2012 (ID cohort; n = 7936). A cohort from the general population, one-to-one matched by sex and year of birth, was used as referents. Data regarding fall-induced health care episodes in inpatient and outpatient specialist care were collected from the National Patient Register for the period 2002-2012.RESULTS: With the exception of falls from one level to another (i.e. fall on and from stairs and steps, ladder and scaffolding; fall from, out of or through building or structure; fall from tree or cliff and diving or jumping into water; or other fall from one level to another), people in the ID cohort were more likely to fall and fall more often than those in the general population cohort. Falls during a vital activity (e.g. attending to personal hygiene or eating) were twice as common among people with ID compared with the general population. When falling, people with ID were more likely to injure their head and legs but less likely to sustain injuries to the thorax and elbow/forearm. They were more likely to have superficial injuries, open wounds and fractures but less likely to have dislocations, sprain and strains. Fall-related health care visits among people with ID were more likely to be in inpatient care and be unplanned. People with ID were also more likely than those in the general population to have a readmission within 30 days.CONCLUSIONS: People with ID are more likely to require specialist care after a fall and also more likely to obtain injuries to the head, compared with the general population. This is important to consider when taking preventive measures to reduce falls and fall-related injuries.
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37.
  • Axmon, A, et al. (författare)
  • Health care utilisation among older persons with intellectual disability and dementia : a registry study
  • 2016
  • Ingår i: Journal of Intellectual Disability Research. - : Wiley. - 0964-2633 .- 1365-2788. ; 60:12, s. 1165-1177
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND: Both persons with intellectual disability (ID) and persons with dementia have high disease burdens, and consequently also high health care needs. As life expectancy increases for persons with ID, the group of persons with the dual diagnosis of ID and dementia will become larger.METHOD: Through national registries, we identified 7936 persons who had received support directed to persons with ID during 2012, and an age- and gender-matched sample from the general population. A national registry was also used to collect information on health care utilisation (excluding primary care) for the period 2002-2012. Health care utilisation was measured as presence and number of planned and unplanned in-patient and out-patient visits, as well as length of stay.RESULTS: In comparison with persons with ID but without dementia, persons with ID and dementia were more likely to have at least one planned out-patient visit (odds ratio [OR] 8.07), unplanned out-patient visit (OR 2.41), planned in-patient visit (OR 2.76) or unplanned in-patient visit (OR 4.19). However, among those with at least one of each respective outcome, the average number of visits did not differ between those with and without dementia. Persons with ID and dementia were less likely to have at least one planned out-patient visit than persons with dementia in the general population sample (OR 0.40), but more likely to have at least one unplanned in-patient visit (OR 1.90). No statistically significant differences were found for having at least one unplanned out-patient or planned in-patient visit. Nevertheless, among those with at least one unplanned out-patient visit, the number of visits was higher in the general population sample.CONCLUSIONS: Persons with ID and dementia are less likely to receive planned health care than persons with dementia in the general population. They have, however, higher levels of unplanned health care utilisation. This may be an indication that the current support system is not sufficient to meet the challenges of increased longevity among persons with ID.
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38.
  • Axmon, A., et al. (författare)
  • Hospital readmissions among older people with intellectual disability in comparison with the general population
  • 2019
  • Ingår i: Journal of Intellectual Disability Research. - : Wiley. - 0964-2633 .- 1365-2788. ; 63:6, s. 593-602
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Older people with intellectual disability have high multimorbidity and poor physical and mental health compared with the general population. Consequently, they have a greater need for health care. Hospital readmissions may be an indicator of the quality of health care. However, so far, only a few studies have investigated this outcome in populations of people with intellectual disability. None has focused on older people. Method: We identified a cohort of people with intellectual disability aged 55+ years and alive at the end of 2012 (n = 7936). Moreover, we established a reference cohort from the general population, one-to-one matched by sex and year of birth. Data on hospital visits during the period 2002–2012 were collected from the Swedish National Patient Register. Readmissions were defined as unplanned visits with the same diagnosis occurring within 30 days of discharge and with no planned visit for the same diagnosis during this time. Results: Compared with the general population, people with intellectual disability had increased risk of readmissions for diseases of the nervous system [relative risk (RR) 2.62], respiratory system (RR 1.48), digestive system (RR 1.40) and musculoskeletal system and connective tissue (RR 2.10). Within these diagnostic groups, increased risks were found for arthropathies (RR 3.73), disorders of gallbladder, biliary tract and pancreas (RR 1.78), other diseases of intestines (RR 1.30), and other forms of heart disease (RR 1.23). Decreased risk of readmissions was found for mental and behavioural disorders (RR 0.78) and diseases of the circulatory system (RR 0.64). Conclusions: The increased risk for readmissions related to diseases of the nervous and musculoskeletal systems has a clear relation to the prevalence of comorbidities in these areas. People with intellectual disability often also have inborn limitations and damages in these systems which with time lead to complications and risk for diseases, which can be difficult to discover. The increased risk for readmissions for disease of the respiratory system, together with the already known increased prevalence of such diagnoses and their occurrence as a cause for death, warrants further investigations and considerations of potential preventive measures. The pattern of readmissions among older people with intellectual disability cannot be explained solely by a higher prevalence of disorders in this group. Our finding of increased risks for readmissions for diseases in the digestive system could be interpreted as communication problems, which sometimes result in too rapid discharges and their consequential early readmissions.
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39.
  • Axmon, A, et al. (författare)
  • Psychiatric diagnoses in older people with intellectual disability in comparison with the general population a register study
  • 2018
  • Ingår i: Epidemiology and Psychiatric Sciences. - 2045-7960. ; 27:5, s. 479-491
  • Tidskriftsartikel (refereegranskat)abstract
    • AIMS: To describe the occurrence of psychiatric diagnoses in a specialist care setting in older people with intellectual disability (ID) in relation to those found in the same age group in the general population.METHOD: A cohort of people with ID (n = 7936), aged 55 years or more in 2012, was identified, as was an age and sex-matched cohort from the general population (n = 7936). Information regarding psychiatric diagnoses during 2002-2012 was collected from the National Patient Register, which contains records from all inpatient care episodes and outpatient specialist visits in Sweden. The mean age at the start of data collection (i.e. January 1st, 2002) was 53 years (range 44-85 years).RESULTS: Seventeen per cent (n = 1382) of the people in the ID cohort had at least one psychiatric diagnosis recorded during the study period. The corresponding number in the general population cohort was 10% (n = 817), which translates to an odds ratio (OR) of 1.84. The diagnoses recorded for the largest number of people in the ID cohort were 'other' (i.e. not included in any of the diagnostic groups) psychiatric diagnoses (10% of the cohort had at least one such diagnosis recorded) and affective disorders (7%). In the general population cohort, the most common diagnoses were affective disorders (4%) and alcohol/substance-abuse-related disorders (4%). An increased odds of having at least one diagnosis was found for all investigated diagnoses except for alcohol/substance-abuse-related disorders (OR = 0.56). The highest odds for the ID cohort was found for diagnosis of psychotic disorder (OR = 10.4) followed by attention deficit/hyperactive disorder (OR = 3.81), dementia (OR = 2.71), personality disorder (OR = 2.67), affective disorder (OR = 1.74) and anxiety disorder (OR = 1.36). People with ID also had an increased odds of psychiatric diagnoses not included in any of these groups (OR = 8.02). The percentage of people with ID who had at least one diagnosis recorded during the study period decreased from more than 30% among those aged 55-59 years in 2012 (i.e. born 1953-1957) to approximately 20% among those aged 75+ years in 2012 (i.e. born in or before 1937).CONCLUSIONS: Older people with ID seem to be more likely to have psychiatric diagnoses in inpatient or outpatient specialist care than their peers in the general population. If this is an effect of different disorder prevalence, diagnostic difficulties or differences in health care availability remains unknown. More research is needed to understand the diagnostic and treatment challenges of psychiatric disorders in this vulnerable group.
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40.
  • Axmon, A, et al. (författare)
  • Psychiatric diagnoses in relation to severity of intellectual disability and challenging behaviors : a register study among older people
  • 2018
  • Ingår i: Aging and Mental Health. - : Informa UK Limited. - 1364-6915 .- 1360-7863. ; 22:10, s. 1344-1350
  • Tidskriftsartikel (refereegranskat)abstract
    • OBJECTIVE: To investigate the possible association between severity of intellectual disability (ID) and presence of challenging behavior, respectively, on diagnoses of psychiatric disorders among older people with ID.METHODS: People with a diagnosis of ID in inpatient or specialist outpatient care in 2002-2012 were identified (n = 2147; 611 with mild ID, 285 with moderate ID, 255 with severe or profound ID, and 996 with other/unspecified ID). Moreover, using impairment of behavior as a proxy for challenging behavior, 627 people with, and 1514 without such behavior were identified.RESULTS: Severe/profound ID was associated with lower odds of diagnoses of psychotic, affective, and anxiety disorders than was mild/moderate ID. People with moderate ID had higher odds than those with mild ID of having diagnoses of affective disorders. Diagnoses of psychotic, affective, and anxiety disorders, and dementia were more common among people with challenging behavior than among those without.CONCLUSIONS: People with severe/profound ID had lower odds of receiving psychiatric diagnoses than those with mild and moderate ID. Whether this is a result of differences in prevalence of disorders or diagnostic difficulties is unknown. Further, challenging behaviors were associated with diagnoses of psychiatric disorders. However, the nature of this association remains unclear.
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41.
  • Bergström, Göran, 1964, et al. (författare)
  • Prevalence of Subclinical Coronary Artery Atherosclerosis in the General Population
  • 2021
  • Ingår i: Circulation. - Philadelphia : American Heart Association. - 0009-7322 .- 1524-4539. ; 144:12, s. 916-929
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Early detection of coronary atherosclerosis using coronary computed tomography angiography (CCTA), in addition to coronary artery calcification (CAC) scoring, may help inform prevention strategies. We used CCTA to determine the prevalence, severity, and characteristics of coronary atherosclerosis and its association with CAC scores in a general population.Methods: We recruited 30 154 randomly invited individuals age 50 to 64 years to SCAPIS (the Swedish Cardiopulmonary Bioimage Study). The study includes individuals without known coronary heart disease (ie, no previous myocardial infarctions or cardiac procedures) and with high-quality results from CCTA and CAC imaging performed using dedicated dual-source CT scanners. Noncontrast images were scored for CAC. CCTA images were visually read and scored for coronary atherosclerosis per segment (defined as no atherosclerosis, 1% to 49% stenosis, or ≥50% stenosis). External validity of prevalence estimates was evaluated using inverse probability for participation weighting and Swedish register data.Results: In total, 25 182 individuals without known coronary heart disease were included (50.6% women). Any CCTA-detected atherosclerosis was found in 42.1%; any significant stenosis (≥50%) in 5.2%; left main, proximal left anterior descending artery, or 3-vessel disease in 1.9%; and any noncalcified plaques in 8.3% of this population. Onset of atherosclerosis was delayed on average by 10 years in women. Atherosclerosis was more prevalent in older individuals and predominantly found in the proximal left anterior descending artery. Prevalence of CCTA-detected atherosclerosis increased with increasing CAC scores. Among those with a CAC score >400, all had atherosclerosis and 45.7% had significant stenosis. In those with 0 CAC, 5.5% had atherosclerosis and 0.4% had significant stenosis. In participants with 0 CAC and intermediate 10-year risk of atherosclerotic cardiovascular disease according to the pooled cohort equation, 9.2% had CCTA-verified atherosclerosis. Prevalence estimates had excellent external validity and changed marginally when adjusted to the age-matched Swedish background population.Conclusions: Using CCTA in a large, random sample of the general population without established disease, we showed that silent coronary atherosclerosis is common in this population. High CAC scores convey a significant probability of substantial stenosis, and 0 CAC does not exclude atherosclerosis, particularly in those at higher baseline risk.
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42.
  • Bergström, Göran, et al. (författare)
  • Prevalence of Subclinical Coronary Artery Atherosclerosis in the General Population
  • 2021
  • Ingår i: Circulation. - : Wolters Kluwer. - 0009-7322 .- 1524-4539. ; 144:12, s. 916-929
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Early detection of coronary atherosclerosis using coronary computed tomography angiography (CCTA), in addition to coronary artery calcification (CAC) scoring, may help inform prevention strategies. We used CCTA to determine the prevalence, severity, and characteristics of coronary atherosclerosis and its association with CAC scores in a general population.Methods: We recruited 30 154 randomly invited individuals age 50 to 64 years to SCAPIS (the Swedish Cardiopulmonary Bioimage Study). The study includes individuals without known coronary heart disease (ie, no previous myocardial infarctions or cardiac procedures) and with high-quality results from CCTA and CAC imaging performed using dedicated dual-source CT scanners. Noncontrast images were scored for CAC. CCTA images were visually read and scored for coronary atherosclerosis per segment (defined as no atherosclerosis, 1% to 49% stenosis, or ≥50% stenosis). External validity of prevalence estimates was evaluated using inverse probability for participation weighting and Swedish register data.Results: In total, 25 182 individuals without known coronary heart disease were included (50.6% women). Any CCTA-detected atherosclerosis was found in 42.1%; any significant stenosis (≥50%) in 5.2%; left main, proximal left anterior descending artery, or 3-vessel disease in 1.9%; and any noncalcified plaques in 8.3% of this population. Onset of atherosclerosis was delayed on average by 10 years in women. Atherosclerosis was more prevalent in older individuals and predominantly found in the proximal left anterior descending artery. Prevalence of CCTA-detected atherosclerosis increased with increasing CAC scores. Among those with a CAC score >400, all had atherosclerosis and 45.7% had significant stenosis. In those with 0 CAC, 5.5% had atherosclerosis and 0.4% had significant stenosis. In participants with 0 CAC and intermediate 10-year risk of atherosclerotic cardiovascular disease according to the pooled cohort equation, 9.2% had CCTA-verified atherosclerosis. Prevalence estimates had excellent external validity and changed marginally when adjusted to the age-matched Swedish background population.Conclusions: Using CCTA in a large, random sample of the general population without established disease, we showed that silent coronary atherosclerosis is common in this population. High CAC scores convey a significant probability of substantial stenosis, and 0 CAC does not exclude atherosclerosis, particularly in those at higher baseline risk.
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43.
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44.
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45.
  • Boone, Sebastiaan C., et al. (författare)
  • Evaluation of the Value of Waist Circumference and Metabolomics in the Estimation of Visceral Adipose Tissue
  • 2022
  • Ingår i: American Journal of Epidemiology. - : Oxford University Press (OUP). - 0002-9262 .- 1476-6256. ; 191:5, s. 886-899
  • Tidskriftsartikel (refereegranskat)abstract
    • Visceral adipose tissue (VAT) is a strong prognostic factor for cardiovascular disease and a potential target for cardiovascular risk stratification. Because VAT is difficult to measure in clinical practice, we estimated prediction models with predictors routinely measured in general practice and VAT as outcome using ridge regression in 2,501 middle-aged participants from the Netherlands Epidemiology of Obesity study, 2008-2012. Adding waist circumference and other anthropometric measurements on top of the routinely measured variables improved the optimism-adjusted R-2 from 0.50 to 0.58 with a decrease in the root-mean-square error (RMSE) from 45.6 to 41.5 cm(2) and with overall good calibration. Further addition of predominantly lipoprotein-related metabolites from the Nightingale platform did not improve the optimism-corrected R-2 and RMSE. The models were externally validated in 370 participants from the Prospective Investigation of Vasculature in Uppsala Seniors (PIVUS, 2006-2009) and 1,901 participants from the Multi-Ethnic Study of Atherosclerosis (MESA, 2000-2007). Performance was comparable to the development setting in PIVUS (R-2 = 0.63, RMSE = 42.4 cm(2), calibration slope = 0.94) but lower in MESA (R-2 = 0.44, RMSE = 60.7 cm(2), calibration slope = 0.75). Our findings indicate that the estimation of VAT with routine clinical measurements can be substantially improved by incorporating waist circumference but not by metabolite measurements.
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46.
  • Briley-Saebo, Karen C., et al. (författare)
  • Clearance of iron oxide particles in rat liver : effect of hydrated particle size and coating material on liver metabolism
  • 2006
  • Ingår i: Investigative Radiology. - : Ovid Technologies (Wolters Kluwer Health). - 0020-9996 .- 1536-0210. ; 41:7, s. 560-571
  • Tidskriftsartikel (refereegranskat)abstract
    • OBJECTIVES: We sought to evaluate the effect of the particle size and coating material of various iron oxide preparations on the rate of rat liver clearance. MATERIALS AND METHODS: The following iron oxide formulations were used in this study: dextran-coated ferumoxide (size = 97 nm) and ferumoxtran-10 (size = 21 nm), carboxydextran-coated SHU555A (size = 69 nm) and fractionated SHU555A (size = 12 nm), and oxidized-starch coated materials either unformulated NC100150 (size = 15 nm) or formulated NC100150 injection (size = 12 nm). All formulations were administered to 165 rats at 2 dose levels. Quantitative liver R2* values were obtained during a 63-day time period. The concentration of iron oxide particles in the liver was determined by relaxometry, and these values were used to calculate the particle half-lives in the liver. RESULTS: After the administration of a high dose of iron oxide, the half-life of iron oxide particles in rat liver was 8 days for dextran-coated materials, 10 days for carboxydextran materials, 14 days for unformulated oxidized-starch, and 29 days for formulated oxidized-starch. CONCLUSIONS: The results of the study indicate that materials with similar coating but different sizes exhibited similar rates of liver clearance. It was, therefore, concluded that the coating material significantly influences the rate of iron oxide clearance in rat liver.
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47.
  • Du, Enzai, et al. (författare)
  • Global patterns of terrestrial nitrogen and phosphorus limitation
  • 2020
  • Ingår i: Nature Geoscience. - : Springer Science and Business Media LLC. - 1752-0894 .- 1752-0908. ; 13:3, s. 221-226
  • Tidskriftsartikel (refereegranskat)abstract
    • Nitrogen (N) and phosphorus (P) limitation constrains the magnitude of terrestrial carbon uptake in response to elevated carbon dioxide and climate change. However, global maps of nutrient limitation are still lacking. Here we examined global N and P limitation using the ratio of site-averaged leaf N and P resorption efficiencies of the dominant species across 171 sites. We evaluated our predictions using a global database of N- and P-limitation experiments based on nutrient additions at 106 and 53 sites, respectively. Globally, we found a shift from relative P to N limitation for both higher latitudes and precipitation seasonality and lower mean annual temperature, temperature seasonality, mean annual precipitation and soil clay fraction. Excluding cropland, urban and glacial areas, we estimate that 18% of the natural terrestrial land area is significantly limited by N, whereas 43% is relatively P limited. The remaining 39% of the natural terrestrial land area could be co-limited by N and P or weakly limited by either nutrient alone. This work provides both a new framework for testing nutrient limitation and a benchmark of N and P limitation for models to constrain predictions of the terrestrial carbon sink.
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48.
  • Eklöf, Hampus, et al. (författare)
  • Renal artery stenosis evaluated with magnetic resonance angiography using intraarterial pressure gradient as the standard of reference : A multireader study
  • 2005
  • Ingår i: Acta Radiologica. - : SAGE Publications. - 0284-1851 .- 1600-0455. ; 46:8, s. 802-809
  • Tidskriftsartikel (refereegranskat)abstract
    • PURPOSE: To evaluate 3D-Gd-magnetic resonance angiography (MRA) in detecting hemodynamically significant renal artery stenosis (RAS). MATERIAL AND METHODS: Thirty patients evaluated for atherosclerotic RAS by MRA and digital subtraction angiography (DSA) were retrospectively included. Standard of reference for hemodynamically significant RAS was a transstenotic gradient of 15 mmHg. DSA visualized 60 main renal arteries and 9 accessory arteries. Pressure gradient measurement (PGM) was available from 61 arteries. Three radiologists evaluated all examinations independently in a blinded fashion. RESULTS: RAS was present in 26 arteries. On MRA, each reader identified 4 of 9 accessory renal arteries, a detection rate of 44%. The three readers correctly classified 22/25/22 of the 26 vessels with a significant gradient as > or =60% RAS and 31/25/32 of the 35 with no significant gradient as < 60% RAS on MRA. Interobserver agreement was substantial. MRA image quality was adequate for RAS evaluations in all patients. ROC curves indicated that MRA is an adequate method for evaluating RAS. When screening for RAS, a 50% diameter reduction cut-off is better than 60%. RAS with 40-80% diameter reductions accounted for 65% of discrepancies. CONCLUSION: MRA is an adequate method for evaluating RAS limited mainly by poor detection rate for accessory renal arteries.
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49.
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50.
  • Fausto, Robert S., et al. (författare)
  • Greenland ice sheet melt area from MODIS (2000–2014)
  • 2015
  • Ingår i: Geological Survey of Denmark and Greenland Bulletin. - 1811-4598 .- 1604-8156. ; 33, s. 57-60
  • Tidskriftsartikel (refereegranskat)abstract
    • The Greenland ice sheet is an excellent observatory for global climate change. Meltwater from the 1.8 million km2 large ice sheet influences oceanic temperature and salinity, nutrient fluxes and global sea level (IPCC 2013). Surface reflectivity is a key driver of surface melt rates (Box et al. 2012). Mapping of different ice-sheet surface types provides a clear indicator of where changes in ice-sheet surface reflectivity are most prominent. Here, we present an updated version of a surface classification algorithm that utilises NASA’s Moderateresolution Imaging Spectroradiometer (MODIS) sensor on the Terra satellite to systematically monitor ice-sheet surface melt (Fausto et al. 2007). Our aim is to determine the areal extent of three surface types over the 2000–2014 period: glacier ice, melting snow (including percolation areas) and dry snow (Cuff ey & Paterson 2010). Monthly 1 km2 resolution surface-type grids can be downloaded via the CryoClim internet portal (www.cryoclim.net). In this report, we briefly describe the updated classification algorithm, validation of surface types and inter-annual variability in surface types.
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