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1.
Glob Chang Biol ; 30(5): e17317, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38747199

RESUMEN

Each year, an average of 45 tropical cyclones affect coastal areas and potentially impact forests. The proportion of the most intense cyclones has increased over the past four decades and is predicted to continue to do so. Yet, it remains uncertain how topographical exposure and tree characteristics can mediate the damage caused by increasing wind speed. Here, we compiled empirical data on the damage caused by 11 cyclones occurring over the past 40 years, from 74 forest plots representing tropical regions worldwide, encompassing field data for 22,176 trees and 815 species. We reconstructed the wind structure of those tropical cyclones to estimate the maximum sustained wind speed (MSW) and wind direction at the studied plots. Then, we used a causal inference framework combined with Bayesian generalised linear mixed models to understand and quantify the causal effects of MSW, topographical exposure to wind (EXP), tree size (DBH) and species wood density (ρ) on the proportion of damaged trees at the community level, and on the probability of snapping or uprooting at the tree level. The probability of snapping or uprooting at the tree level and, hence, the proportion of damaged trees at the community level, increased with increasing MSW, and with increasing EXP accentuating the damaging effects of cyclones, in particular at higher wind speeds. Higher ρ decreased the probability of snapping and to a lesser extent of uprooting. Larger trees tended to have lower probabilities of snapping but increased probabilities of uprooting. Importantly, the effect of ρ decreasing the probabilities of snapping was more marked for smaller than larger trees and was further accentuated at higher MSW. Our work emphasises how local topography, tree size and species wood density together mediate cyclone damage to tropical forests, facilitating better predictions of the impacts of such disturbances in an increasingly windier world.


Asunto(s)
Tormentas Ciclónicas , Bosques , Árboles , Clima Tropical , Viento , Árboles/crecimiento & desarrollo , Teorema de Bayes
2.
Health Qual Life Outcomes ; 22(1): 37, 2024 Apr 29.
Artículo en Inglés | MEDLINE | ID: mdl-38685039

RESUMEN

BACKGROUND: Approximately 1.5 million adults in the UK have a learning disability. The difference between age at death for this group and the general population is 26 years for females and 22 years for males. The NHS Long Term Plan (January 2019) recognises learning disabilities as a clinical priority area. People with a learning disability are often excluded from research by design or lack of reasonable adjustments, and self-reported health status/health-related quality of life questionnaires such as the EQ-5D are often not appropriate for this population. Here, we systematically examine the EQ-5D-3L (its wording, content, and format) using qualitative methods to inform the adaption of the measure for use with adults with mild to moderate learning disabilities. METHODS: Think-aloud interviews with carers/advocates of learning-disabled adults were undertaken to explore the difficulties with completing the EQ-5D-3L. Alternative wording, language, structure, and images were developed using focus groups, stakeholder reference groups, and an expert panel. Data analysis followed a framework method. RESULTS: The dimensions and levels within the EQ-5D-3L were deemed appropriate for adults with mild to moderate learning disabilities. Consensus on wording, structure, and images was reached through an iterative process, and an adapted version of the EQ-5D-3L was finalised. CONCLUSION: The EQ-5D-3L adapted for adults with mild to moderate intellectual/learning disabilities can facilitate measurement of self-reported health status. Research is underway to assess the potential use of the adaptation for economic evaluation.


Asunto(s)
Discapacidades para el Aprendizaje , Calidad de Vida , Humanos , Adulto , Masculino , Femenino , Discapacidades para el Aprendizaje/psicología , Encuestas y Cuestionarios , Estado de Salud , Reino Unido , Grupos Focales , Investigación Cualitativa , Adulto Joven , Psicometría
3.
Proc Natl Acad Sci U S A ; 118(28)2021 07 13.
Artículo en Inglés | MEDLINE | ID: mdl-34260386

RESUMEN

Anthropogenic nutrient enrichment is driving global biodiversity decline and modifying ecosystem functions. Theory suggests that plant functional types that fix atmospheric nitrogen have a competitive advantage in nitrogen-poor soils, but lose this advantage with increasing nitrogen supply. By contrast, the addition of phosphorus, potassium, and other nutrients may benefit such species in low-nutrient environments by enhancing their nitrogen-fixing capacity. We present a global-scale experiment confirming these predictions for nitrogen-fixing legumes (Fabaceae) across 45 grasslands on six continents. Nitrogen addition reduced legume cover, richness, and biomass, particularly in nitrogen-poor soils, while cover of non-nitrogen-fixing plants increased. The addition of phosphorous, potassium, and other nutrients enhanced legume abundance, but did not mitigate the negative effects of nitrogen addition. Increasing nitrogen supply thus has the potential to decrease the diversity and abundance of grassland legumes worldwide regardless of the availability of other nutrients, with consequences for biodiversity, food webs, ecosystem resilience, and genetic improvement of protein-rich agricultural plant species.


Asunto(s)
Fabaceae/fisiología , Pradera , Internacionalidad , Nitrógeno/farmacología , Fósforo/farmacología , Biodiversidad , Biomasa , Fabaceae/efectos de los fármacos , Probabilidad
4.
Alzheimers Dement ; 20(4): 2752-2765, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38415908

RESUMEN

INTRODUCTION: Alzheimer's disease (AD) trial participants are often screened for eligibility by brain amyloid positron emission tomography/cerebrospinal fluid (PET/CSF), which is inefficient as many are not amyloid positive. Use of blood-based biomarkers may reduce screen failures. METHODS: We recruited 755 non-Hispanic White, 115 Hispanic, 112 non-Hispanic Black, and 19 other minority participants across groups of cognitively normal (n = 417), mild cognitive impairment (n = 312), or mild AD (n = 272) participants. Plasma amyloid beta (Aß)40, Aß42, Aß42/Aß40, total tau, phosphorylated tau (p-tau)181, and p-tau217 were measured; amyloid PET/CSF (n = 956) determined amyloid positivity. Clinical, blood biomarker, and ethnicity/race differences associated with amyloid status were evaluated. RESULTS: Greater impairment, older age, and carrying an apolipoprotein E (apoE) ε4 allele were associated with greater amyloid burden. Areas under the receiver operating characteristic curve for amyloid status of plasma Aß42/Aß40, p-tau181, and p-tau217 with amyloid positivity were ≥ 0.7117 for all ethnoracial groups (p-tau217, ≥0.8128). Age and apoE ε4 adjustments and imputation of biomarker values outside limit of quantitation provided small improvement in predictive power. DISCUSSION: Blood-based biomarkers are highly associated with amyloid PET/CSF results in diverse populations enrolled at clinical trial sites. HIGHLIGHTS: Amyloid beta (Aß)42/Aß40, phosphorylated tau (p-tau)181, and p-tau 217 blood-based biomarkers predicted brain amyloid positivity. P-tau 217 was the strongest predictor of brain amyloid positivity. Biomarkers from diverse ethnic, racial, and clinical cohorts predicted brain amyloid positivity. Community-based populations have similar Alzheimer's disease (AD) biomarker levels as other populations. A prescreen process with blood-based assays may reduce the number of AD trial screen failures.


Asunto(s)
Enfermedad de Alzheimer , Disfunción Cognitiva , Humanos , Enfermedad de Alzheimer/líquido cefalorraquídeo , Péptidos beta-Amiloides/líquido cefalorraquídeo , Proteínas tau/líquido cefalorraquídeo , Disfunción Cognitiva/diagnóstico , Disfunción Cognitiva/líquido cefalorraquídeo , Encéfalo , Tomografía de Emisión de Positrones , Biomarcadores/líquido cefalorraquídeo
5.
Oecologia ; 202(3): 561-575, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-37436476

RESUMEN

Plant-plant interactions are integral to the establishment and persistence of diversity in plant communities. For annual plant species that depend on seeds to regenerate, seed characteristics that confer fitness advantages may mediate processes such as plant-plant interactions. Seed mass is known to vary widely and has been shown to associate with species' differences in stress tolerance and competitive effects. However, understanding of how seed mass influences species' responses to competition is less well understood. Using natural assemblages of six closely related annual plant species in Western Australia, we implemented a thinning study to assess how seed mass influences the outcomes of plant-plant interactions. We found relatively weak evidence for competition or facilitation among species. Our strongest results indicated that heavy-seeded species had lower survivorship than light-seeded species when interacting with heterospecifics. Seed mass was also negatively related to overall survival, counter to expectations. These findings indicate some evidence for trade-offs mediated by seed mass in this system. However, we acknowledge that other factors may have influenced our results, such as the use of natural assemblages (rather than using sowing experiments) and the presence of important small-scale environmental variation not captured with our choice of abiotic variables. Further research is required to clarify the role of seed mass in this diverse annual system, ideally including many focal species, and using sowing experiments.


Asunto(s)
Plantas , Semillas , Estaciones del Año
6.
Proc Natl Acad Sci U S A ; 117(8): 4218-4227, 2020 02 25.
Artículo en Inglés | MEDLINE | ID: mdl-32034102

RESUMEN

When plants establish outside their native range, their ability to adapt to the new environment is influenced by both demography and dispersal. However, the relative importance of these two factors is poorly understood. To quantify the influence of demography and dispersal on patterns of genetic diversity underlying adaptation, we used data from a globally distributed demographic research network comprising 35 native and 18 nonnative populations of Plantago lanceolata Species-specific simulation experiments showed that dispersal would dilute demographic influences on genetic diversity at local scales. Populations in the native European range had strong spatial genetic structure associated with geographic distance and precipitation seasonality. In contrast, nonnative populations had weaker spatial genetic structure that was not associated with environmental gradients but with higher within-population genetic diversity. Our findings show that dispersal caused by repeated, long-distance, human-mediated introductions has allowed invasive plant populations to overcome environmental constraints on genetic diversity, even without strong demographic changes. The impact of invasive plants may, therefore, increase with repeated introductions, highlighting the need to constrain future introductions of species even if they already exist in an area.


Asunto(s)
Flujo Génico , Variación Genética , Plantago/genética , Demografía , Especies Introducidas , Filogenia , Plantago/química
7.
New Phytol ; 236(3): 839-851, 2022 11.
Artículo en Inglés | MEDLINE | ID: mdl-35922934

RESUMEN

A range of functional trait-based approaches have been developed to investigate community assembly processes, but most ignore how traits covary within communities. We combined existing approaches - community-weighted means (CWMs) and functional dispersion (FDis) - with a metric of trait covariance to examine assembly processes in five angiosperm assemblages along a moisture gradient in Australia's subtropics. In addition to testing hypotheses about habitat filtering along the gradient, we hypothesized that trait covariance would be strongest at both ends of the moisture gradient and weakest in the middle, reflecting trade-offs associated with light capture in productive sites and moisture stress in dry sites. CWMs revealed evidence of climatic filtering, but FDis patterns were less clear. As hypothesized, trait covariance was weakest in the middle of the gradient but unexpectedly peaked at the second driest site due to the emergence of a clear drought tolerance-drought avoidance spectrum. At the driest site, the same spectrum was truncated at the 'avoider' end, revealing important information about habitat filtering in this system. Our focus on trait covariance revealed the nature and strength of trade-offs imposed by light and moisture availability, complementing insights gained about community assembly from existing trait-based approaches.


Asunto(s)
Ecosistema , Plantas , Bosque Lluvioso , Fenotipo , Filogenia
8.
Ecol Appl ; 32(6): e2636, 2022 09.
Artículo en Inglés | MEDLINE | ID: mdl-35404495

RESUMEN

Functional traits are proxies for a species' ecology and physiology and are often correlated with plant vital rates. As such they have the potential to guide species selection for restoration projects. However, predictive trait-based models often only explain a small proportion of plant performance, suggesting that commonly measured traits do not capture all important ecological differences between species. Some residual variation in vital rates may be evolutionarily conserved and captured using taxonomic groupings alongside common functional traits. We tested this hypothesis using growth rate data for 17,299 trees and shrubs from 80 species of Eucalyptus and 43 species of Acacia, two hyper-diverse and co-occurring genera, collected from 497 neighborhood plots in 137 Australian mixed-species revegetation plantings. We modeled relative growth rates of individual plants as a function of environmental conditions, species-mean functional traits, and neighbor density and diversity, across a moisture availability gradient. We then assessed whether the strength and direction of these relationships differed between the two genera. We found that the inclusion of genus-specific relationships offered a significant but modest improvement to model fit (1.6%-1.7% greater R2 than simpler models). More importantly, almost all correlates of growth rate differed between Eucalyptus and Acacia in strength, direction, or how they changed along the moisture gradient. These differences mapped onto physiological differences between the genera that were not captured solely by measured functional traits. Our findings suggest taxonomic groupings can capture or mediate variation in plant performance missed by common functional traits. The inclusion of taxonomy can provide a more nuanced understanding of how functional traits interact with abiotic and biotic conditions to drive plant performance, which may be important for constructing trait-based frameworks to improve restoration outcomes.


Asunto(s)
Acacia , Eucalyptus , Australia , Hojas de la Planta/fisiología , Plantas , Árboles/fisiología
9.
Oecologia ; 198(4): 865-875, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-34999943

RESUMEN

Environmentally cued germination may play an important role in promoting coexistence in Mediterranean annual plant systems if it causes niche differentiation across heterogeneous microsite conditions. In this study, we tested how microsite conditions experienced by seeds in the field and light conditions in the laboratory influenced germination in 12 common annual plant species occurring in the understorey of the York gum-jam woodlands in southwest Western Australia. Specifically, we hypothesized that if germination promotes spatial niche differentiation, then we should observe species-specific germination responses to light. In addition, we hypothesized that species' laboratory germination response may depend on the microsite conditions experienced by seeds while buried. We tested the laboratory germination response of seeds under diurnally fluctuating light and complete darkness, which were collected from microsites spanning local-scale environmental gradients known to influence community structure in this system. We found that seeds of 6 out of the 12 focal species exhibited significant positive germination responses to light, but that the magnitude of these responses varied greatly with the relative light requirement for germination ranging from 0.51 to 0.86 for these species. In addition, germination increased significantly across a gradient of canopy cover for two species, but we found little evidence to suggest that species' relative light requirement for germination varied depending on seed bank microsite conditions. Our results suggest that variability in light availability may promote coexistence in this system and that the microsite conditions seeds experience in the intra-growing season period can further nuance species germination behaviour.


Asunto(s)
Germinación , Semillas , Australia , Germinación/fisiología , Luz , Latencia en las Plantas/fisiología , Estaciones del Año , Semillas/fisiología , Temperatura
10.
Qual Life Res ; 31(4): 1191-1198, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-34661806

RESUMEN

The disruptions to health research during the COVID-19 pandemic are being recognized globally, and there is a growing need for understanding the pandemic's impact on the health and health preferences of patients, caregivers, and the general public. Ongoing and planned health preference research (HPR) has been affected due to problems associated with recruitment, data collection, and data interpretation. While there are no "one size fits all" solutions, this commentary summarizes the key challenges in HPR within the context of the pandemic and offers pragmatic solutions and directions for future research. We recommend recruitment of a diverse, typically under-represented population in HPR using online, quota-based crowdsourcing platforms, and community partnerships. We foresee emerging evidence on remote, and telephone-based HPR modes of administration, with further studies on the shifts in preferences related to health and healthcare services as a result of the pandemic. We believe that the recalibration of HPR, due to what one would hope is an impermanent change, will permanently change how we conduct HPR in the future.


Asunto(s)
COVID-19 , Pandemias , COVID-19/epidemiología , Humanos , Calidad de Vida/psicología
11.
J Environ Manage ; 302(Pt B): 114051, 2022 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-34773778

RESUMEN

Land-use change, and associated land clearing/conversion and fragmentation are major drivers of biodiversity decline across the globe. The spread of invasive species is a well-recognised consequence of land-use change. The extent and intensity of invasion however is often difficult to assess due to a lack of temporal data. Using detailed mapping information for 130, 950 km2 of sub-coastal Queensland, Australia and results from field surveys we investigated changes to land-use, the extent of remnant (intact) vegetation and the spread of prominent invasive plant species over time (1997-2018). In the 50 years prior to 1997 the area underwent significant land development (mostly for livestock grazing and crops), resulting in a reduction of 45% of its remnant vegetation. Despite key policy developments aimed at protecting the remaining vegetation and species, 7392 km2 was cleared/converted between 1997 and 2017, mainly for the expansion of grazing and cropping lands. Vegetation types specifically listed for national protection under these policies were some of the greatest affected, highlighting the need for improved implementation and regulation of these control measures. Within remaining fragments of remnant vegetation, the cover and presence of two invasive perennial grass species indian couch (Bothriochloa pertusa) and buffel grass (Cenchrus ciliaris) increased significantly during this time period. There was also a moderate increase in the cover and presence of the annual herb Parthenium weed (Parthenium hysterophorus). The spread of these species within the landscape likely reflects an 'invasion debt', incurred from an intense history of land-use within the region and we predict this trend will continue to threaten remnant ecosystems.


Asunto(s)
Biodiversidad , Ecosistema , Australia , Conservación de los Recursos Naturales , Especies Introducidas , Malezas
12.
Ecol Lett ; 24(5): 970-983, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33638576

RESUMEN

Life history strategies are fundamental to the ecology and evolution of organisms and are important for understanding extinction risk and responses to global change. Using global datasets and a multiple response modelling framework we show that trait-climate interactions are associated with life history strategies for a diverse range of plant species at the global scale. Our modelling framework informs our understanding of trade-offs and positive correlations between elements of life history after accounting for environmental context and evolutionary and trait-based constraints. Interactions between plant traits and climatic context were needed to explain variation in age at maturity, distribution of mortality across the lifespan and generation times of species. Mean age at maturity and the distribution of mortality across plants' lifespan were under evolutionary constraints. These findings provide empirical support for the theoretical expectation that climatic context is key to understanding trait to life history relationships globally.


Asunto(s)
Rasgos de la Historia de Vida , Evolución Biológica , Ecología , Fenotipo , Plantas
13.
Ecol Lett ; 24(11): 2378-2393, 2021 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-34355467

RESUMEN

Genetic differentiation and phenotypic plasticity jointly shape intraspecific trait variation, but their roles differ among traits. In short-lived plants, reproductive traits may be more genetically determined due to their impact on fitness, whereas vegetative traits may show higher plasticity to buffer short-term perturbations. Combining a multi-treatment greenhouse experiment with observational field data throughout the range of a widespread short-lived herb, Plantago lanceolata, we (1) disentangled genetic and plastic responses of functional traits to a set of environmental drivers and (2) assessed how genetic differentiation and plasticity shape observational trait-environment relationships. Reproductive traits showed distinct genetic differentiation that largely determined observational patterns, but only when correcting traits for differences in biomass. Vegetative traits showed higher plasticity and opposite genetic and plastic responses, masking the genetic component underlying field-observed trait variation. Our study suggests that genetic differentiation may be inferred from observational data only for the traits most closely related to fitness.


Asunto(s)
Máscaras , Plantago , Adaptación Fisiológica , Biomasa , Fenotipo
14.
Value Health ; 24(4): 568-574, 2021 04.
Artículo en Inglés | MEDLINE | ID: mdl-33840435

RESUMEN

OBJECTIVES: To estimate the impact of using EQ5D-5L (5L) compared with EQ5D-3L (3L) in cost-effectiveness analyses in 6 countries with 3L and 5L values: Germany, Japan, Korea, The Netherlands, China, and Spain. METHODS: Eight cost-effectiveness analyses based on clinical studies with 3L provided 11 pairwise comparisons. We estimated cost-effectiveness by applying the appropriate country values for 3L to observed responses. We re-estimated cost-effectiveness for each country by predicting the 5L tariff score for each respondent, for each country, using a previously published mapping method. We compared results in terms of impact on estimated incremental quality-adjusted life-year (QALY) gain and cost-effectiveness ratios. RESULTS: For most countries the impact of moving from 3L to 5L is to lower the incremental QALY gain in the majority of comparisons. The only exception to this was Japan, where 4 out of 11 cases (37%) saw lower QALYs gained when using 5L. The mean and median reductions in health gain, in those case studies where 5L does lead to lower health gain, are largest in The Netherlands (84% mean reduction, 41% median reduction), Germany (68% and 27%), and Spain (30% and 31%). For most countries, those studies where 5L leads to lower health gain see larger reductions than the gains in studies showing the opposite tendency. CONCLUSIONS: Overall, 3L and 5L are not interchangeable in these countries. Differences between results are large, but the direction of change can be unpredictable. These findings should prompt further investigation into the reasons for differences.


Asunto(s)
Análisis Costo-Beneficio/métodos , Indicadores de Salud , Años de Vida Ajustados por Calidad de Vida , China , Alemania , Humanos , Japón , Países Bajos , Ensayos Clínicos Controlados Aleatorios como Asunto , República de Corea , España
15.
Can J Diet Pract Res ; 82(1): 45-48, 2021 03 01.
Artículo en Inglés | MEDLINE | ID: mdl-33320791

RESUMEN

Purpose: To explore knowledge, attitudes, and behaviour related to physical activity (PA) and sedentariness among registered dietitians (RDs) in family health teams in Ontario.Methods: This cross-sectional, descriptive study utilized a semi-structured interview guide to conduct qualitative interviews with 20 RDs. Self-administered questionnaires were used to assess personal PA (short version of the International Physical Activity Questionnaire) and sedentary behaviour (Sedentary Behavior Questionnaire).Results: Thematic analysis indicated that, in general, participants had good knowledge of PA and sedentariness. They were knowledgeable about the PA guidelines. They had positive attitudes toward PA and nonsedentariness, stating that both are important in the prevention and treatment of chronic conditions. Quantitative analysis indicated they had moderate-to-high PA levels and were fairly sedentary.Conclusions: This study supports the position that RDs can serve as excellent role models for PA. Though participants had basic knowledge, RDs may benefit from additional education regarding PA and sedentariness when counselling.


Asunto(s)
Nutricionistas , Estudios Transversales , Ejercicio Físico , Conocimientos, Actitudes y Práctica en Salud , Humanos , Encuestas y Cuestionarios
16.
Aust Crit Care ; 34(3): 195-203, 2021 05.
Artículo en Inglés | MEDLINE | ID: mdl-32972819

RESUMEN

BACKGROUND: Emergency department (ED) triage is the process of prioritising patients by medical urgency. Delays in intensive care unit (ICU) admission can adversely affect patients. OBJECTIVES: This study aimed to identify characteristics associated with ICU admission for patients triaged as Australasian Triage Scale (ATS) 3 but subsequently admitted to the ICU within 24 h of triage. METHODS: This retrospective, observational cohort study was conducted in a public teaching hospital in Queensland, Australia. Patients older than 18 y triaged with an ATS 3 and admitted to the ICU within 24 h of triage or admitted to the ward between January 1, 2012, and December 31, 2012, were included. The demographic and clinical profiles of ICU admissions vs. all other ward admissions for patients triaged an ATS of 3 were compared. Multivariable regression analysis compared characteristics of patients triaged with an ATS of 3 who did and did not require ICU transfer. Descriptive data are reported as n (%) and median and interquartile range (IQR). Regression analysis is reported as adjusted odds ratios (aORs) with 95% confidence intervals (95% CIs). RESULTS: Of the 27 454 adult ED presentations triaged with an ATS of 3, 22.4% (n = 6138) required hospital admission, comprising 5302 individuals, 2.1% of whom (n = 110) were admitted to the ICU within 24 h of triage. Age- and sex-adjusted predictors of ICU admission for patients triaged with an ATS of 3 included infectious (aOR: 3.7; 95% CI: 2.0-6.9), neurological (aOR: 2.8; 95% CI: 1.6-5.0), and gastrointestinal disorders (aOR: 2.2; 95% CI 1.2-3.5); arriving by ambulance; arriving after hours; or arriving on weekends. Regardless of diagnosis or sex, persons older than 80 y were less likely to be admitted to the ICU (aOR: 0.4; 95% CI: 0.2-0.8). CONCLUSIONS: Patients triaged as ATS 3 presenting on weekends or after hours, and those with infectious, gastrointestinal, or neurological conditions warrant careful attention as these factors were associated with higher odds of ICU admission. Ongoing staff education regarding triage and signs of deterioration are important to prevent avoidable outcomes.


Asunto(s)
Enfermedad Crítica , Admisión del Paciente , Adulto , Servicio de Urgencia en Hospital , Humanos , Unidades de Cuidados Intensivos , Estudios Retrospectivos , Triaje
17.
Glob Chang Biol ; 26(5): 3079-3090, 2020 05.
Artículo en Inglés | MEDLINE | ID: mdl-31994234

RESUMEN

Abiotic environmental change, local species extinctions and colonization of new species often co-occur. Whether species colonization is driven by changes in abiotic conditions or reduced biotic resistance will affect community functional composition and ecosystem management. We use a grassland experiment to disentangle effects of climate warming and community diversity on plant species colonization. Community diversity had dramatic impacts on the biomass, richness and traits of plant colonists. Three times as many species colonized the monocultures than the high diversity 17 species communities (~30 vs. 10 species), and colonists collectively produced 10 times as much biomass in the monocultures than the high diversity communities (~30 vs. 3 g/m2 ). Colonists with resource-acquisitive strategies (high specific leaf area, light seeds, short heights) accrued more biomass in low diversity communities, whereas species with conservative strategies accrued most biomass in high diversity communities. Communities with higher biomass of resident C4 grasses were more resistant to colonization by legume, nonlegume forb and C3 grass colonists, but not by C4 grass colonists. Compared with effects of diversity, 6 years of 3°C-above-ambient temperatures had little impact on plant colonization. Warmed subplots had ~3 fewer colonist species than ambient subplots and selected for heavier seeded colonists. They also showed diversity-dependent changes in biomass of C3 grass colonists, which decreased under low diversity and increased under high diversity. Our findings suggest that species colonization is more strongly affected by biotic resistance from residents than 3°C of climate warming. If these results were extended to invasive species management, preserving community diversity should help limit plant invasion, even under climate warming.


Asunto(s)
Biodiversidad , Ecosistema , Biomasa , Especies Introducidas , Poaceae
18.
Intern Med J ; 50(5): 572-581, 2020 05.
Artículo en Inglés | MEDLINE | ID: mdl-31336021

RESUMEN

BACKGROUND: Dedicated geriatric models of care are becoming more prevalent due to the complexity of, and increase in, acute healthcare presentations for older patients. For older people, a long stay in the emergency department (ED) may reflect the complexity of their presentation, or deficiencies in systems that manage these complexities. AIMS: To identify predictors of a long ED length of stay (LLoS) for patients ≥65 years old. METHODS: Linked hospital information systems data from a large, public Australian ED were analysed in this retrospective cohort study. LLoS was defined as the 75th percentile (617 min). Multivariate regression identified LLoS predictors for admissions and discharges separately. RESULTS: Of 16 791 ED presentations made by older people, 4192 experienced a LLoS; 55% were admitted. Increasing age was associated with an increasing ED LoS. Factors most predictive of LLoS for both admitted and discharged patients included: investigations (both pathology and imaging), less urgent Australasian triage scale categories and after-hours arrival. Ambulance arrival did not increase the risk of a LLoS for patients eventually admitted, but conferred nearly a twofold increased risk for a LLoS for discharged older persons (adjusted odds ratios = 1.9; 95% confidence interval 1.5-2.4). CONCLUSIONS: This study assists clinicians and decision-makers to identify reasons why older persons have a LLoS, whether admitted or discharged. Interventions to streamline care for older patients arriving after-hours and who require imaging and pathology are required. LoS targets should consider age distribution. The use of ED LoS as a quality of care indicator should be assessed for admissions and discharges, separately.


Asunto(s)
Servicio de Urgencia en Hospital , Triaje , Anciano , Anciano de 80 o más Años , Australia/epidemiología , Humanos , Tiempo de Internación , Estudios Retrospectivos
19.
Proc Biol Sci ; 286(1915): 20192221, 2019 11 20.
Artículo en Inglés | MEDLINE | ID: mdl-31744440

RESUMEN

Metabolic scaling theory (MST) is one of ecology's most high-profile general models and can be used to link size distributions and productivity in forest systems. Much of MST's foundation is based on size distributions following a power law function with a scaling exponent of -2, a property assumed to be consistent in steady-state ecosystems. We tested the theory's generality by comparing actual size distributions with those predicted using MST parameters assumed to be general. We then used environmental variables and functional traits to explain deviation from theoretical expectations. Finally, we compared values of relative productivity predicted using MST with a remote-sensed measure of productivity. We found that fire-prone heath communities deviated from MST-predicted size distributions, whereas fire-sensitive rainforests largely agreed with the theory. Scaling exponents ranged from -1.4 to -5.3. Deviation from the power law assumption was best explained by specific leaf area, which varies along fire frequency and moisture gradients. While MST may hold in low-disturbance systems, we show that it cannot be applied under many environmental contexts. The theory should remain general, but understanding the factors driving deviation from MST and subsequent refinements is required if it is to be applied robustly across larger scales.


Asunto(s)
Ecosistema , Modelos Biológicos , Metabolismo
20.
Nanotechnology ; 30(24): 245705, 2019 Jun 14.
Artículo en Inglés | MEDLINE | ID: mdl-30849771

RESUMEN

Orthorhombic tin monosulfide (SnS) consists of layers of covalently bound Sn and S atoms held together by weak van der Waals forces and is a stable two-dimensional material with potentially useful properties in emerging applications such as valleytronics. Large-scale sustainable synthesis of few-layer (e.g., 1-10 layers) SnS is a challenge, which also slows progress in understanding their properties as a function of number of layers. Herein we describe solvothermal synthesis of SnS in water or ethylene glycol. The latter yields a flower-like morphology where the petals are SnS nanoplates and sonication and separation of these flowers via differential centrifugation yields 1-10 layer SnS nanoplates. The direct optical absorption edges of these SnS nanoplates blue-shift due to quantum confinement from 1.33 to 1.88 eV as the thickness (number of layers) is decreased from ∼5 nm (10 layers) to ∼2 nm (4 layers).

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