31 research outputs found

    Differential Behavior of Young Eucalyptus Clones in Response to Nitrogen Supply

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    Eucalyptus requires large amounts of nitrogen (N); however, it responds in diverse manners to the application of this nutrient. The aim of this study was to evaluate the differential performance in growth, mineral nutrition, and gas exchanges of N-fertilized Eucalyptus clones. The treatments consisted of two Eucalyptus clones (VM-01 and I-144) and six N application rates (0, 0.74, 2.93, 4.39, 5.85, and 8 mmol L-1 NH4NO3) arranged in a randomized complete block design with five replications. VM-01 had greater plant height and greater height/collar diameter ratio, as well as higher leaf concentrations of all macronutrients and of Cu, Fe, Mo, and Zn. In terms of total and root dry matter production, root/shoot ratio, and collar diameter, as well as stomatal conductance and transpiration, I-144 performed better. The performance of the clones was clearly differentiated, and the growth of I-144, despite lower leaf N concentration, was in general better than VM-01

    Basin-wide variation in tree hydraulic safety margins predicts the carbon balance of Amazon forests

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    Tropical forests face increasing climate risk1,2, yet our ability to predict their response to climate change is limited by poor understanding of their resistance to water stress. Although xylem embolism resistance thresholds (for example, Ψ50) and hydraulic safety margins (for example, HSM50) are important predictors of drought-induced mortality risk3–5, little is known about how these vary across Earth’s largest tropical forest. Here, we present a pan-Amazon, fully standardized hydraulic traits dataset and use it to assess regional variation in drought sensitivity and hydraulic trait ability to predict species distributions and long-term forest biomass accumulation. Parameters Ψ50 and HSM50 vary markedly across the Amazon and are related to average long-term rainfall characteristics. Both Ψ50 and HSM50 influence the biogeographical distribution of Amazon tree species. However, HSM50 was the only significant predictor of observed decadal-scale changes in forest biomass. Old-growth forests with wide HSM50 are gaining more biomass than are low HSM50 forests. We propose that this may be associated with a growth–mortality trade-off whereby trees in forests consisting of fast-growing species take greater hydraulic risks and face greater mortality risk. Moreover, in regions of more pronounced climatic change, we find evidence that forests are losing biomass, suggesting that species in these regions may be operating beyond their hydraulic limits. Continued climate change is likely to further reduce HSM50 in the Amazon6,7, with strong implications for the Amazon carbon sink

    Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

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    Background: Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. // Methods: We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung's disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. // Findings: We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung's disease) from 264 hospitals (89 in high-income countries, 166 in middle-income countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in low-income countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. // Interpretation: Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between low-income, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

    Basin-wide variation in tree hydraulic safety margins predicts the carbon balance of Amazon forests

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    This is the final version. Available on open access from Nature Research via the DOI in this recordData availability: The pan-Amazonian HT dataset (Ψ 50, Ψ dry and HSM50) and branch wood density per species per site, as well as forest dynamic and climate data per plot presented in this study are available as a ForestPlots.net data package at https://forestplots.net/data-packages/Tavares-et-al-2023. Basal area weighted mean LMA is shown in Supplementary Table 2. Species stem wood density data were obtained from Global Wood Density database65,66. Species WDA data were extracted from ref. 45.Code availability: The codes to recreate the main analyses and the main figures presented in this study are available as a ForestPlots.net data package at https://forestplots.net/data-packages/Tavares-et-al-2023.Tropical forests face increasing climate risk, yet our ability to predict their response to climate change is limited by poor understanding of their resistance to water stress. Although xylem embolism resistance thresholds (for example, Ψ 50) and hydraulic safety margins (for example, HSM50) are important predictors of drought-induced mortality risk, little is known about how these vary across Earth’s largest tropical forest. Here, we present a pan-Amazon, fully standardized hydraulic traits dataset and use it to assess regional variation in drought sensitivity and hydraulic trait ability to predict species distributions and long-term forest biomass accumulation. Parameters Ψ 50 and HSM50 vary markedly across the Amazon and are related to average long-term rainfall characteristics. Both Ψ 50 and HSM50 influence the biogeographical distribution of Amazon tree species. However, HSM50 was the only significant predictor of observed decadal-scale changes in forest biomass. Old-growth forests with wide HSM50 are gaining more biomass than are low HSM50 forests. We propose that this may be associated with a growth–mortality trade-off whereby trees in forests consisting of fast-growing species take greater hydraulic risks and face greater mortality risk. Moreover, in regions of more pronounced climatic change, we find evidence that forests are losing biomass, suggesting that species in these regions may be operating beyond their hydraulic limits. Continued climate change is likely to further reduce HSM50 in the Amazon, with strong implications for the Amazon carbon sink

    CRISE MIASTÊNICA

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    SÍNDROME DE GUILLAIN-BARRÉ

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    Distúrbios de leitura e escrita em portadora do vírus da imunodeficiência humana: estudo de caso Reading and writing disorders in a patient with the human immunodeficiency virus: a case study

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    Este artigo tem por objetivo descrever o caso de uma criança soropositiva para o para o vírus da imunodeficiência humana com distúrbios de leitura e escrita, analisando as estratégias mais funcionais e os resultados obtidos nas avaliações pré e pós-terapia fonoaudiológica. Foi aplicado um programa terapêutico fonoaudiológico fechado (15 sessões), com duração de 50 minutos, semanalmente, em uma criança do sexo feminino com 11 anos de idade, paciente do Laboratório de Investigação Fonoaudiológica em Leitura e Escrita. Foram utilizadas estratégias variadas enfocando as áreas de processamento auditivo, consciência fonológica e fonêmica, leitura e escrita. Ao início e término do referido programa, foram realizadas avaliações de linguagem escrita e exames audiológicos. Após as 15 sessões, verificou-se melhora tanto na decodificação de palavras e produção escrita de pequenos textos (adequados do ponto de vista da competência genérica) como no processamento da informação auditiva. As estratégias mais motivadoras foram: atividades com poemas infantis, atividades no computador, palavras cruzadas, caça-palavras e jogo de histórias escritas para complementação. No caso em questão, trabalhar com estratégias dentro do foco de interesse da criança e balancear o novo com o desconhecido contribuíram para o sucesso funcional do processo terapêutico em leitura e escrita. A avaliação audiológica (comportamental, eletroacústica e eletrofisiológica), antes e após um programa terapêutico fechado, é importante, pois é fundamental para monitorar a evolução terapêutica, bem como para avaliar a relevância desse programa.<br>This paper had the aim to describe the case of a human immunodeficiency virus-positive child with reading and writing disorders, analyzing the functional strategies and the results obtained in the pre and post speech-language therapy evaluations. A weekly closed speech-language therapeutic program (of 15 sessions), lasting 50 minutes each, was carried out with an 11 year-old female patient of the Speech and Hearing Investigation Laboratory in Reading and Writing. Different strategies focusing on auditory processing, phonological and phonemic awareness, reading and writing were used. Writing evaluations and audiological exams were performed at the beginning and the end of the aforementioned program. After the 15 sessions, an improvement was observed in words decoding and written production of small texts (adequate from the generic competence point of view), as well as in auditory information processing. The most motivating strategies were: activities with child poems, computer activities, crosswords, word search, and game of written stories for complementing. In this specific case, working with strategies that were interesting for the child and balancing the new with the unknown contributed to the functional success of the therapeutic process in reading and writing. The audiological assessment is important before and after a closed therapeutic program as it is crucial to both monitor the therapeutic evolution and to evaluate the relevance of this program
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