| 1. |
- Knudsen, Gitte M, et al.
(författare)
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Guidelines for the content and format of PET brain data in publications and archives : A consensus paper
- 2020
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Ingår i: Journal of Cerebral Blood Flow and Metabolism. - : SAGE Publications. - 0271-678X .- 1559-7016. ; 40:8, s. 1576-1585
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Tidskriftsartikel (refereegranskat)abstract
- It is a growing concern that outcomes of neuroimaging studies often cannot be replicated. To counteract this, the magnetic resonance (MR) neuroimaging community has promoted acquisition standards and created data sharing platforms, based on a consensus on how to organize and share MR neuroimaging data. Here, we take a similar approach to positron emission tomography (PET) data. To facilitate comparison of findings across studies, we first recommend publication standards for tracer characteristics, image acquisition, image preprocessing, and outcome estimation for PET neuroimaging data. The co-authors of this paper, representing more than 25 PET centers worldwide, voted to classify information as mandatory, recommended, or optional. Second, we describe a framework to facilitate data archiving and data sharing within and across centers. Because of the high cost of PET neuroimaging studies, sample sizes tend to be small and relatively few sites worldwide have the required multidisciplinary expertise to properly conduct and analyze PET studies. Data sharing will make it easier to combine datasets from different centers to achieve larger sample sizes and stronger statistical power to test hypotheses. The combining of datasets from different centers may be enhanced by adoption of a common set of best practices in data acquisition and analysis.
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| 2. |
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| 3. |
- Murray-Tortarolo, Guillermo, et al.
(författare)
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The dry season intensity as a key driver of NPP trends
- 2016
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Ingår i: Geophysical Research Letters. - 1944-8007. ; 43:6, s. 2632-2639
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Tidskriftsartikel (refereegranskat)abstract
- We analyze the impacts of changing dry season length and intensity on vegetation productivity and biomass. Our results show a wetness asymmetry in dry ecosystems, with dry seasons becoming drier and wet seasons becoming wetter, likely caused by climate change. The increasingly intense dry seasons were consistently correlated with a decreasing trend in net primary productivity (NPP) and biomass from different products and could potentially mean a reduction of 10–13% in NPP by 2100. We found that annual NPP in dry ecosystems is particularly sensitive to the intensity of the dry season, whereas an increase in precipitation during the wet season has a smaller effect. We conclude that changes in water availability over the dry season affect vegetation throughout the whole year, driving changes in regional NPP. Moreover, these results suggest that usage of seasonal water fluxes is necessary to improve our understanding of the link between water availability and the land carbon cycle.
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| 4. |
- Potapov, Anton M., et al.
(författare)
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Global fine-resolution data on springtail abundance and community structure
- 2024
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Ingår i: Scientific Data. - : Nature Publishing Group. - 2052-4463. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Springtails (Collembola) inhabit soils from the Arctic to the Antarctic and comprise an estimated ~32% of all terrestrial arthropods on Earth. Here, we present a global, spatially-explicit database on springtail communities that includes 249,912 occurrences from 44,999 samples and 2,990 sites. These data are mainly raw sample-level records at the species level collected predominantly from private archives of the authors that were quality-controlled and taxonomically-standardised. Despite covering all continents, most of the sample-level data come from the European continent (82.5% of all samples) and represent four habitats: woodlands (57.4%), grasslands (14.0%), agrosystems (13.7%) and scrublands (9.0%). We included sampling by soil layers, and across seasons and years, representing temporal and spatial within-site variation in springtail communities. We also provided data use and sharing guidelines and R code to facilitate the use of the database by other researchers. This data paper describes a static version of the database at the publication date, but the database will be further expanded to include underrepresented regions and linked with trait data.
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| 5. |
- Bang, Casper N., et al.
(författare)
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Antihypertensive treatment with β-blockade in patients with asymptomatic aortic stenosis and association with cardiovascular events
- 2017
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Ingår i: Journal of the American Heart Association. - : Wiley-Blackwell Publishing Inc.. - 2047-9980. ; 6:12
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Tidskriftsartikel (refereegranskat)abstract
- Background: Patients with aortic stenosis (AS) often have concomitant hypertension. Antihypertensive treatment with a beta-blocker (Bbl) is frequently avoided because of fear of depression of left ventricular function. However, it remains unclear whether antihypertensive treatment with a Bbl is associated with increased risk of cardiovascular events in patients with asymptomatic mild to moderate AS.Methods and results: We did a post hoc analysis of 1873 asymptomatic patients with mild to moderate AS and preserved left ventricular ejection fraction in the SEAS (Simvastatin and Ezetimibe in Aortic Stenosis) study. Propensity-matched Cox regression and competing risk analyses were used to assess risk ratios for all-cause mortality, sudden cardiac death, and cardiovascular death. A total of 932 (50%) patients received Bbl at baseline. During a median follow-up of 4.3 +/- 0.9 years, 545 underwent aortic valve replacement, and 205 died; of those, 101 were cardiovascular deaths, including 40 sudden cardiovascular deaths. In adjusted analyses, Bbl use was associated with lower risk of all-cause mortality (hazard ratio 0.5, 95% confidence interval 0.3-0.7, P<0.001), cardiovascular death (hazard ratio 0.4, 95% confidence interval 0.2-0.7, P<0.001), and sudden cardiac death (hazard ratio 0.2, 95% confidence interval 0.1-0.6, P=0.004). This was confirmed in competing risk analyses (all P<0.004). No interaction was detected with AS severity (all P>0.1).Conclusions: In post hoc analyses Bbl therapy did not increase the risk of all-cause mortality, sudden cardiac death, or cardiovascular death in patients with asymptomatic mild to moderate AS. A prospective study may be warranted to determine if Bbl therapy is in fact beneficial.
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| 6. |
- Bang, Casper N, et al.
(författare)
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Effect of Randomized Lipid Lowering With Simvastatin and Ezetimibe on Cataract Development (from the Simvastatin and Ezetimibe in Aortic Stenosis Study)
- 2015
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Ingår i: American Journal of Cardiology. - : Elsevier. - 0002-9149 .- 1879-1913. ; 116:12, s. 1840-1844
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Tidskriftsartikel (refereegranskat)abstract
- Recent American College of Cardiology/American Heart Association guidelines on statin initiation on the basis of total atherosclerotic cardiovascular disease risk argue that the preventive effect of statins on cardiovascular events outweigh the side effects, although this is controversial. Studies indicate a possible effect of statin therapy on reducing risk of lens opacities. However, the results are conflicting. The Simvastatin and Ezetimibe in Aortic Stenosis study (NCT00092677) enrolled 1,873 patients with asymptomatic aortic stenosis and no history of diabetes, coronary heart disease, or other serious co-morbidities were randomized (1:1) to double-blind 40 mg simvastatin plus 10 mg ezetimibe versus placebo. The primary end point in this substudy was incident cataract. Univariate and multivariate Cox models were used to analyze: (1) if the active treatment reduced the risk of the primary end point and (2) if time-varying low-density lipoproteins (LDL) cholesterol lowering (annually assessed) was associated with less incident cataract per se. During an average follow-up of 4.3 years, 65 patients (3.5%) developed cataract. Mean age at baseline was 68 years and 39% were women. In Cox multivariate analysis adjusted for age, gender, prednisolone treatment, smoking, baseline LDL cholesterol and high sensitivity C-reactive protein; simvastatin plus ezetimibe versus placebo was associated with 44% lower risk of cataract development (hazard ratio 0.56, 95% confidence interval 0.33 to 0.96, p = 0.034). In a parallel analysis substituting time-varying LDL-cholesterol with randomized treatment, lower intreatment LDL-cholesterol was in itself associated with lower risk of incident cataract (hazard ratio 0.78 per 1 mmol/ml lower total cholesterol, 95% confidence interval 0.64 to 0.93, p = 0.008). In conclusion, randomized treatment with simvastatin plus ezetimibe was associated with a 44% lower risk of incident cataract development. This effect should perhaps be considered in the risk-benefit ratio of statin treatment.
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| 7. |
- Björkman, Anne, 1981, et al.
(författare)
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Tundra Trait Team: A database of plant traits spanning the tundra biome
- 2018
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Ingår i: Global Ecology and Biogeography. - : Wiley. - 1466-822X .- 1466-8238. ; 27:12, s. 1402-1411
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Tidskriftsartikel (refereegranskat)abstract
- © 2018 The Authors Global Ecology and Biogeography Published by John Wiley & Sons Ltd Motivation: The Tundra Trait Team (TTT) database includes field-based measurements of key traits related to plant form and function at multiple sites across the tundra biome. This dataset can be used to address theoretical questions about plant strategy and trade-offs, trait–environment relationships and environmental filtering, and trait variation across spatial scales, to validate satellite data, and to inform Earth system model parameters. Main types of variable contained: The database contains 91,970 measurements of 18 plant traits. The most frequently measured traits (>1,000 observations each) include plant height, leaf area, specific leaf area, leaf fresh and dry mass, leaf dry matter content, leaf nitrogen, carbon and phosphorus content, leaf C:N and N:P, seed mass, and stem specific density. Spatial location and grain: Measurements were collected in tundra habitats in both the Northern and Southern Hemispheres, including Arctic sites in Alaska, Canada, Greenland, Fennoscandia and Siberia, alpine sites in the European Alps, Colorado Rockies, Caucasus, Ural Mountains, Pyrenees, Australian Alps, and Central Otago Mountains (New Zealand), and sub-Antarctic Marion Island. More than 99% of observations are georeferenced. Time period and grain: All data were collected between 1964 and 2018. A small number of sites have repeated trait measurements at two or more time periods. Major taxa and level of measurement: Trait measurements were made on 978 terrestrial vascular plant species growing in tundra habitats. Most observations are on individuals (86%), while the remainder represent plot or site means or maximums per species. Software format: csv file and GitHub repository with data cleaning scripts in R; contribution to TRY plant trait database (www.try-db.org) to be included in the next version release.
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| 8. |
- Greve, Anders M., et al.
(författare)
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Contrasting Hemodynamic Mechanisms of Losartan- vs. Atenolol-Based Antihypertensive Treatment : A LIFE Study
- 2012
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Ingår i: American Journal of Hypertension. - : Oxford University Press (OUP). - 0895-7061 .- 1941-7225. ; 25:9, s. 1017-1023
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND Pharmaceutical differences in central hemodynamics might influence cardiac response to antihypertensive treatment despite similar lowering of brachial blood pressure (BP). METHODS Data from all patients with at least two echocardiographic examinations in the Losartan Intervention For Endpoint Reduction in Hypertension (LIFE) echocardiographic substudy (n = 801); high-risk patients on losartan- vs. atenolol-based antihypertensive therapy. Echocardiography was performed annually for 4 years to measure stroke index (SI), heart rate, cardiac index (CI), conduit artery stiffness assessed as pulse pressure/stroke index (PP/SI) and total peripheral resistance index (TPRI). RESULTS Atenolol- and losartan-based therapy reduced BP similarly (cumulative difference in mean brachial blood pressure 0.3 mm Hg, P = 0.65). After 4 years the cumulative means of SI and heart rate were 1.8 ml/m(2) higher and 5.7 beats/min lower on atenolol-based treatment, respectively (both P < 0.001). This kept CI below baseline in atenolol-treated patients, whereas in the losartan group CI was unchanged from baseline throughout the study. TPRI was decreased more and remained lower in the losartan group (cumulative difference in mean TPRI 287 dynes/sec(-5)/cm/m(2), P < 0.001). These findings partly explained univariate differences in systolic- and diastolic function indices between the two treatments; fully adjusted losartan was only associated with a smaller left atrial diameter (cumulative mean difference 0.07 cm; 95% confidence intervals, -0.13 to -0.01, P = 0.03). CONCLUSIONS Contrasting hemodynamics impacted cardiac response to similar reductions in brachial BP on losartan- vs. atenolol-based therapy. The similar reduction of PP/SI suggests that the antihypertensive regimens used in the LIFE study had comparable effects on arterial stiffness (LIFE study; NCT00338260)
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| 9. |
- Greve, Anders M., et al.
(författare)
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Resting heart rate and risk of adverse cardiovascular outcomes in asymptomatic aortic stenosis : The SEAS study
- 2015
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Ingår i: International Journal of Cardiology. - : Elsevier BV. - 0167-5273 .- 1874-1754. ; 180, s. 122-128
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Tidskriftsartikel (refereegranskat)abstract
- Background: An elevated resting heart rate (RHR) may be an early sign of cardiac failure, but its prognostic value during watchful waiting in asymptomatic aortic stenosis (AS) is largely unknown. Methods: RHR was determined by annual ECGs in the Simvastatin and Ezetimibe in Aortic Stenosis (SEAS) study of asymptomatic mild-to-moderate AS patients. Primary endpoint in this substudy was major cardiovascular events (MCEs) and secondary outcomes its individual components. Multivariable Cox-models using serially-measured RHR were used to examine the prognostic impact of RHR per se. Results: 1563 patients were followed for a mean of 4.3 years (6751 patient-years of follow-up), 553 (35%) MCEs occurred, 10% (n = 151) died, including 75 cardiovascular deaths. In multivariable analysis, baseline RHR was independently associated with MCEs (HR 1.1 per 10 min(-1) faster, 95% CI: 1.0-1.3) and cardiovascular mortality (HR 1.3 per 10 min(-1) faster, 95% CI: 1.0-1.7, both p <= 0.03). Updating RHR with annual in-study reexaminations, time-varying RHR was highly associated with excess MCEs (HR 1.1 per 10 min(-1) faster, 95% CI: 1.1-1.3) and cardiovascular mortality (HR 1.4 per 10 min(-1) faster, 95% CI: 1.2-1.7, both p <= 0.006). The association of RHR with MCEs and cardiovascular mortality was not dependent on atrial fibrillation status (both p >= 0.06 for interaction). Conclusions: RHR is independently associated with MCEs and cardiovascular death in asymptomatic AS (Clinicaltrials.gov; unique identifier NCT00092677).
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| 10. |
- Greve, Anders M., et al.
(författare)
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Usefulness of the electrocardiogram in predicting cardiovascular mortality in asymptomatic adults with aortic stenosis (from the Simvastatin and Ezetimibe in Aortic Stenosis study)
- 2014
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Ingår i: American Journal of Cardiology. - : Elsevier. - 0002-9149 .- 1879-1913. ; 114:5, s. 751-756
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Tidskriftsartikel (refereegranskat)abstract
- Hypertension and coronary heart disease are common in aortic stenosis (AS) and may impair prognosis for similar AS severity. Different changes in the electrocardiogram may be reflective of the separate impacts of AS, hypertension, and coronary heart disease, which could lead to enhanced risk stratification in AS. The aim of this study was therefore to examine if combining prognostically relevant electrocardiographic (ECG) findings improves prediction of cardiovascular mortality in asymptomatic AS. All patients with baseline electrocardiograms in the SEAS study were included. The primary end point was cardiovascular death. Backward elimination (p > 0.01) identified heart rate, Q waves, and Cornell voltage-duration product as independently associated with cardiovascular death. Multivariate logistic and Cox regression models were used to evaluate if these 3 ECG variables improved prediction of cardiovascular death. In 1,473 patients followed for a mean of 4.3 years (6,362 patient-years of follow-up), 70 cardiovascular deaths (5%) occurred. In multivariate analysis, heart rate (hazard ratio [FIR] 1.5 per 11.2 minute(-1) [1 SD], 95% confidence interval [CI] 1.2 to 1.8), sum of Q-wave amplitude (HR 1.3 per 2.0 nun [1 SD], 95% CI 1.1 to 1.6), and Cornell voltage-duration product (FIR 1.4 per 763 mm x ms [1 SD], 95% CI 1.2 to 1.7) remained independently associated with cardiovascular death. Combining the prognostic information contained in each of the 3 ECG variables improved integrated discrimination for prediction of cardiovascular death by 2.5%, net reclassification by 14.3%, and area under the curve by 0.06 (all p <= 0.04) beyond other important risk factors. ECG findings add incremental predictive information for cardiovascular mortality in asymptomatic patients with AS.
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