63 research outputs found

    Denial of long-term issues with agriculture on tropical peatlands will have devastating consequences

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    Carbon sequestration potential of second-growth forest regeneration in the Latin American tropics

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    Regrowth of tropical secondary forests following complete or nearly complete removal of forest vegetation actively stores carbon in aboveground biomass, partially counterbalancing carbon emissions from deforestation, forest degradation, burning of fossil fuels, and other anthropogenic sources. We estimate the age and spatial extent of lowland second-growth forests in the Latin American tropics and model their potential aboveground carbon accumulation over four decades. Our model shows that, in 2008, second-growth forests (1 to 60 years old) covered 2.4 million km2 of land (28.1%of the total study area).Over 40 years, these lands can potentially accumulate a total aboveground carbon stock of 8.48 Pg C (petagrams of carbon) in aboveground biomass via low-cost natural regeneration or assisted regeneration, corresponding to a total CO2 sequestration of 31.09 Pg CO2. This total is equivalent to carbon emissions from fossil fuel use and industrial processes in all of Latin America and the Caribbean from1993 to 2014. Ten countries account for 95% of this carbon storage potential, led by Brazil, Colombia, Mexico, and Venezuela. We model future land-use scenarios to guide national carbon mitigation policies. Permitting natural regeneration on 40% of lowland pastures potentially stores an additional 2.0 Pg C over 40 years. Our study provides information and maps to guide national-level forest-based carbon mitigation plans on the basis of estimated rates of natural regeneration and pasture abandonment. Coupled with avoided deforestation and sustainable forestmanagement, natural regeneration of second-growth forests provides a low-costmechanism that yields a high carbon sequestration potential with multiple benefits for biodiversity and ecosystem services. © 2016 The Authors

    Biodiversity recovery of Neotropical secondary forests

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    Old-growth tropical forests harbor an immense diversity of tree species but are rapidly being cleared, while secondary forests that regrow on abandoned agricultural lands increase in extent. We assess how tree species richness and composition recover during secondary succession across gradients in environmental conditions and anthropogenic disturbance in an unprecedented multisite analysis for the Neotropics. Secondary forests recover remarkably fast in species richness but slowly in species composition. Secondary forests take a median time of five decades to recover the species richness of old-growth forest (80% recovery after 20 years) based on rarefaction analysis. Full recovery of species composition takes centuries (only 34% recovery after 20 years). A dual strategy that maintains both old-growth forests and species-rich secondary forests is therefore crucial for biodiversity conservation in human-modified tropical landscapes. Copyright © 2019 The Authors, some rights reserved

    Increasing frailty is associated with higher prevalence and reduced recognition of delirium in older hospitalised inpatients: results of a multi-centre study

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    Purpose: Delirium is a neuropsychiatric disorder delineated by an acute change in cognition, attention, and consciousness. It is common, particularly in older adults, but poorly recognised. Frailty is the accumulation of deficits conferring an increased risk of adverse outcomes. We set out to determine how severity of frailty, as measured using the CFS, affected delirium rates, and recognition in hospitalised older people in the United Kingdom. Methods: Adults over 65 years were included in an observational multi-centre audit across UK hospitals, two prospective rounds, and one retrospective note review. Clinical Frailty Scale (CFS), delirium status, and 30-day outcomes were recorded. Results: The overall prevalence of delirium was 16.3% (483). Patients with delirium were more frail than patients without delirium (median CFS 6 vs 4). The risk of delirium was greater with increasing frailty [OR 2.9 (1.8–4.6) in CFS 4 vs 1–3; OR 12.4 (6.2–24.5) in CFS 8 vs 1–3]. Higher CFS was associated with reduced recognition of delirium (OR of 0.7 (0.3–1.9) in CFS 4 compared to 0.2 (0.1–0.7) in CFS 8). These risks were both independent of age and dementia. Conclusion: We have demonstrated an incremental increase in risk of delirium with increasing frailty. This has important clinical implications, suggesting that frailty may provide a more nuanced measure of vulnerability to delirium and poor outcomes. However, the most frail patients are least likely to have their delirium diagnosed and there is a significant lack of research into the underlying pathophysiology of both of these common geriatric syndromes

    A Randomized Comparison of Methods of Selecting Narrowband UV-B Starting Dose to Treat Chronic Psoriasis

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    Objectives: To compare narrowband UV-B (TL-01 lamp) phototherapy for psoriasis with individual patient starting doses based on minimal erythemal dose (MED) determination vs a standard fixed starting dose and to compare the efficacy of 70% of MED vs 50% of MED starting dose regimens.Design: Single-center, randomized, double-blind, clinical trial.Setting: Department of Dermatology, Ninewells Hospital and Medical School, Dundee, Scotland.Patients: A total of 210 adult patients (207 of skin phototypes I to III) referred for narrowband UV-Bto treat chronic psoriasis. The study was designed to have 90% powerto detect a difference of 3 or more treatments to clearance and/or minimal residual activity (MRA) between groups.Interventions: Narrowband UV-Bphototherapy was given according to 3 standard regimens, differing only by starting dose selection method. The randomly allocated starting doses were (1) a fixed starting dose, (2) 70% of individual MED, and (3) 50% of individual MED. All patients were MED tested to ensure blinding and for safety reasons.Main Outcome Measures: The number of treatments to clearance and/or MRA of psoriasis was the primary efficacy outcome measure, with changes in Psoriasis Area and Severity Index and Psoriasis Disability Index scores as secondary measures. Adverse effects were recorded.Results: There were no significant differences in the number of treatments to clearance and/or MRA across all 3 groups or in the percentages achieving clearance in each group. More uncomfortable erythemas occurred in the 50% of MED starting dose group (39%) than in the 70% of MED starting dose group (24%) or the fixed starting dose group (24%) (P=.07).Conclusions: The methods of determining the starting dose in this predominantly skin phototype I and II population, treated 3 times weekly, with a 20% followed by 10% incremental reduction in dose, did not significantly influence the effectiveness of treatment. Had there been a clinically important difference in efficacy, we would have expected to identify this. Thus, basing starting dose on individual MED assessments may not influence the treatment's efficacy in a skin phototype I to III population, although it remains important for patient safety. It remains possible that in populations containing individuals with a broader range of erythemal sensitivity, basing the starting dose on MED testing could have an important impact on treatment effectiveness.</p

    Dysfunctional posttraumatic cognitions, posttraumatic stress, and depression in children and adolescents exposed to trauma: A network analysis

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    Background: The latest version of the International Classification of Diseases (ICD-11) proposes a posttraumatic stress disorder (PTSD) diagnosis reduced to its core symptoms within the symptom clusters re-experiencing, avoidance and hyperarousal. Since children and adolescents often show a variety of internalizing and externalizing symptoms in the aftermath of traumatic events, the question arises whether such a conceptualization of the PTSD diagnosis is supported in children and adolescents. Furthermore, although dysfunctional posttraumatic cognitions (PTCs) appear to play an important role in the development and persistence of PTSD in children and adolescents, their function within diagnostic frameworks requires clarification. Methods: We compiled a large international data set of 2,313 children and adolescents aged 6 to 18 years exposed to trauma and calculated a network model including dysfunctional PTCs, PTSD core symptoms and depression symptoms. Central items and relations between constructs were investigated. Results: The PTSD re-experiencing symptoms strong or overwhelming emotions and strong physical sensations and the depression symptom difficulty concentrating emerged as most central. Items from the same construct were more strongly connected with each other than with items from the other constructs. Dysfunctional PTCs were not more strongly connected to core PTSD symptoms than to depression symptoms. Conclusions: Our findings provide support that a PTSD diagnosis reduced to its core symptoms could help to disentangle PTSD, depression and dysfunctional PTCs. Using longitudinal data and complementing between-subject with within-subject analyses might provide further insight into the relationship between dysfunctional PTCs, PTSD and depression.</p
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