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- Muscarella, Robert, et al.
(författare)
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The global abundance of tree palms
- 2020
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Ingår i: Global Ecology and Biogeography. - : Wiley. - 1466-822X .- 1466-8238. ; 29:9, s. 1495-1514
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Tidskriftsartikel (refereegranskat)abstract
- AimPalms are an iconic, diverse and often abundant component of tropical ecosystems that provide many ecosystem services. Being monocots, tree palms are evolutionarily, morphologically and physiologically distinct from other trees, and these differences have important consequences for ecosystem services (e.g., carbon sequestration and storage) and in terms of responses to climate change. We quantified global patterns of tree palm relative abundance to help improve understanding of tropical forests and reduce uncertainty about these ecosystems under climate change.LocationTropical and subtropical moist forests.Time periodCurrent.Major taxa studiedPalms (Arecaceae).MethodsWe assembled a pantropical dataset of 2,548 forest plots (covering 1,191 ha) and quantified tree palm (i.e., ≥10 cm diameter at breast height) abundance relative to co‐occurring non‐palm trees. We compared the relative abundance of tree palms across biogeographical realms and tested for associations with palaeoclimate stability, current climate, edaphic conditions and metrics of forest structure.ResultsOn average, the relative abundance of tree palms was more than five times larger between Neotropical locations and other biogeographical realms. Tree palms were absent in most locations outside the Neotropics but present in >80% of Neotropical locations. The relative abundance of tree palms was more strongly associated with local conditions (e.g., higher mean annual precipitation, lower soil fertility, shallower water table and lower plot mean wood density) than metrics of long‐term climate stability. Life‐form diversity also influenced the patterns; palm assemblages outside the Neotropics comprise many non‐tree (e.g., climbing) palms. Finally, we show that tree palms can influence estimates of above‐ground biomass, but the magnitude and direction of the effect require additional work.ConclusionsTree palms are not only quintessentially tropical, but they are also overwhelmingly Neotropical. Future work to understand the contributions of tree palms to biomass estimates and carbon cycling will be particularly crucial in Neotropical forests.
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| 2. |
- Ntalla, Ioanna, et al.
(författare)
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Multi-ancestry GWAS of the electrocardiographic PR interval identifies 202 loci underlying cardiac conduction
- 2020
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- The electrocardiographic PR interval reflects atrioventricular conduction, and is associated with conduction abnormalities, pacemaker implantation, atrial fibrillation (AF), and cardiovascular mortality. Here we report a multi-ancestry (N=293,051) genome-wide association meta-analysis for the PR interval, discovering 202 loci of which 141 have not previously been reported. Variants at identified loci increase the percentage of heritability explained, from 33.5% to 62.6%. We observe enrichment for cardiac muscle developmental/contractile and cytoskeletal genes, highlighting key regulation processes for atrioventricular conduction. Additionally, 8 loci not previously reported harbor genes underlying inherited arrhythmic syndromes and/or cardiomyopathies suggesting a role for these genes in cardiovascular pathology in the general population. We show that polygenic predisposition to PR interval duration is an endophenotype for cardiovascular disease, including distal conduction disease, AF, and atrioventricular pre-excitation. These findings advance our understanding of the polygenic basis of cardiac conduction, and the genetic relationship between PR interval duration and cardiovascular disease. On the electrocardiogram, the PR interval reflects conduction from the atria to ventricles and also serves as risk indicator of cardiovascular morbidity and mortality. Here, the authors perform genome-wide meta-analyses for PR interval in multiple ancestries and identify 141 previously unreported genetic loci.
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| 3. |
- Manini, T. M., et al.
(författare)
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Identification of Sarcopenia Components That Discriminate Slow Walking Speed: A Pooled Data Analysis
- 2020
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Ingår i: Journal of the American Geriatrics Society. - : Wiley. - 0002-8614 .- 1532-5415. ; 68:7, s. 1419-1428
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND The Sarcopenia Definitions and Outcomes Consortium (SDOC) sought to identify cut points for muscle strength and body composition measures derived from dual-energy x-ray absorptiometry (DXA) that discriminate older adults with slow walking speed. This article presents the core analyses used to guide the SDOC position statements. DESIGN Cross-sectional data analyses of pooled data. SETTING University-based research assessment centers. PARTICIPANTS Community-dwelling men (n = 13,652) and women: (n = 5,115) with information on lean mass by DXA, grip strength (GR), and walking speed. MEASUREMENTS Thirty-five candidate sarcopenia variables were entered into sex-stratified classification and regression tree (CART) models to agnostically choose variables and cut points that discriminate slow walkers (<0.80 m/s). Models with alternative walking speed outcomes were also evaluated (<0.60 and <1.0 m/s and walking speed treated continuously). RESULTS CART models identified GR/body mass index (GRBMI) and GR/total body fat (GRTBF) as the primary discriminating variables for slowness in men and women, respectively. Men with GRBMI of 1.05 kg/kg/m(2)or less were approximately four times more likely to be slow walkers than those with GRBMI of greater than 1.05 kg/kg/m(2). Women with GRTBF of less than 0.65 kg/kg were twice as likely to be slow walkers than women with GRTBF of 0.65 kg/kg or greater. Models with alternative walking speed outcomes selected only functions of GR as primary discriminators of slowness in both men and women. DXA-derived lean mass measures did not consistently discriminate slow walkers. CONCLUSION GR with and without adjustments for body size and composition consistently discriminated older adults with slowness. CART models did not select DXA-based lean mass as a primary discriminator of slowness. These results were presented to an SDOC Consensus Panel, who used them and other information to develop the SDOC Position Statements.
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| 4. |
- Cawthon, P. M., et al.
(författare)
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Putative Cut-Points in Sarcopenia Components and Incident Adverse Health Outcomes: AnSDOCAnalysis
- 2020
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Ingår i: Journal of the American Geriatrics Society. - : Wiley. - 0002-8614 .- 1532-5415. ; 68:7, s. 1429-1437
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES Analyses performed by the Sarcopenia Definitions and Outcomes Consortium (SDOC) identified cut-points in several metrics of grip strength for consideration in a definition of sarcopenia. We describe the associations between the SDOC-identified metrics of low grip strength (absolute or standardized to body size/composition); low dual-energy x-ray absorptiometry (DXA) lean mass as previously defined in the literature (appendicular lean mass [ALM]/ht(2)); and slowness (walking speed <.8 m/s) with subsequent adverse outcomes (falls, hip fractures, mobility limitation, and mortality). DESIGN Individual-level, sex-stratified pooled analysis. We calculated odds ratios (ORs) or hazard ratios (HRs) for incident falls, mobility limitation, hip fractures, and mortality. Follow-up time ranged from 1 year for falls to 8.8 +/- 2.3 years for mortality. SETTING Eight prospective observational cohort studies. PARTICIPANTS A total of 13,421 community-dwelling men and 4,828 community-dwelling women. MEASUREMENTS Grip strength by hand dynamometry, gait speed, and lean mass by DXA. RESULTS Low grip strength (absolute or standardized to body size/composition) was associated with incident outcomes, usually independently of slowness, in both men and women. ORs and HRs generally ranged from 1.2 to 3.0 for those below vs above the cut-point. DXA lean mass was not consistently associated with these outcomes. When considered together, those who had both muscle weakness by absolute grip strength (<35.5 kg in men and <20 kg in women) and slowness were consistently more likely to have a fall, hip fracture, mobility limitation, or die than those without either slowness or muscle weakness. CONCLUSION Older men and women with both muscle weakness and slowness have a higher likelihood of adverse health outcomes. These results support the inclusion of grip strength and walking speed as components in a summary definition of sarcopenia.
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