Variação da fitofisionomia e dinâmica em florestas alagáveis de igapó na Amazônia central relacionada aos distúrbios

Black water igapó forests are classified as oligotrophic ecosystems, influenced by rivers of acid pH, low sediment load, poor in nutrients with a phytophysionomy triggered by hydro-edaphic factors. In this study, we estimated the carbon storage and sequestration in aboveground wood biomass in the Uatumã Sustainable Development Reserve. In order to analyze along the topographic gradient the impacts that the Balbina Hydroelectric Power Plant (HPP) caused, three plots of one hectare were installed in the igapó floodplains of the Abacate River (undisturbed system) and three plots of one hectare in the igapó of the Uatumã River as a disturbed system. All trees with diameter at breast height (DBH) above 10 cm were inventoried and tree heights were estimated by specific non-linear regression model between DBH and tree height. The density of the species was estimated from studies performed in other Central Amazonian black-water igapós. The most abundant species were sampled for tree-ring analysis to estimate tree ages and annual diameter increments. Parameters of DBH, height and wood density of all the trees were used to estimate the aboveground wood biomass and the carbon stock (47% of dry biomass) using a pantropical allometric model. The mean age was estimated by a non- linear regression model through DBH and increment rates, with the age structure of the forest being estimated for each topographic level. A low species richness was detected at the lower topography in the igapó impacted by the HPP, in comparison to the undisturbed system and other Central Amazonian igapós, in the same way, the higher elevation of the disturbed system presented species richness similar to the non-flooded terra firme. The estimates of biomass and carbon stock showed a tendency to increase with decreasing topography. The mean age of the forest showed a significant correlation with tree density, basal area, average wood density, mean diameter increment rates and average residence time of the carbon (carbon stock/carbon sequestration of wood biomass), while the flood duration only showed significant correlations with tree density and species richness. The high biomass production and low residence time of the igapó at the intermediate topography of the Uatumã River, compared to the same elevation at the Abacate River, resulted from the high abundance of pioneer species with short longevity, high diameter increment rates and low wood densities. The obtained results suggest that it is not possible to associate the disturbances caused by the hydrological changes with stand ́s structure and dynamic, but that the igapós of the Uatumã River basin present several stages of secondary succession, possibly as a consequence of past disturbances associated by extreme hydro-climatic conditions. Based on this we suggest further studies to give more insights on the impact of natural and anthropogenic associated with changes of the hydrological cycle in this vulnerable oligotrophic ecosystem.Florestas de igapó de água preta são classificadas como ecossistemas oligotróficos, banhadas por rios de pH ácido, baixa carga de sedimentos e pobre em nutrientes, e com uma fitofisionomia condicionada por fatores hidro-edáficos. Nesse estudo, estimamos o estoque e sequestro de carbono na biomassa lenhosa na Reserva de Desenvolvimento Sustentável do Uatumã. A fim de analisar no gradiente topográfico os impactos que a Usina Hidrelétrica (UHE) de Balbina causou, três parcelas de um hectare do Rio Abacate foram selecionadas como sistema não-perturbado e três parcelas de um hectare no Rio Uatumã como sistema perturbado. Todas as árvores com diâmetro à altura do peito (DAP) acima de 10 cm foram inventariadas e a altura foi estimada por meio de modelos específicos de regressão não linear a partir da relação DAP e altura. A densidade das espécies foi estimada a partir de trabalhos realizados em outros igapós de água-preta ao longo de toda a Bacia Amazônica. As espécies mais abundantes foram coletadas para análise de anéis de crescimento e a partir disto foram estimadas as idade e taxas anuais de incremento diamétrico. Parâmetros de DAP, altura e densidade da madeira de todas as árvores forma utilizados para estimar a biomassa lenhosa acima do solo e o estoque de carbono (47% da biomassa seca) por meio de um modelo alométrico pantropical. A idade média foi estimada por modelo de regressão não-linear através do DAP e taxas de incremento. Com isso a estrutura etária da floresta foi estimada para cada nível topográfico. Foi detectado nesse estudo uma baixa diversidade de espécie nas cotas mais baixas no sistema impactado pela UHE, em comparação ao não perturbado e a outros igapós da Amazônia, da mesma forma a cota mais alta mostrou riqueza de espécies similar à terra-firme. As estimativas de biomassa e estoque de carbono apresentaram uma tendência de aumento à medida que o gradiente topográfico diminui. A idade média da floresta apresentou correlação significativa com a densidade de árvores, área basal, densidade média da madeira, taxas médias de incremento em diâmetro e tempo médio de residência do carbono (estoque de C/sequestro de C na biomassa lenhosa), enquanto que a duração da inundação só apresentou correlação com a densidade das árvores e riqueza de espécies. A maior produtividade no igapó do Rio Uatumã resultante de uma taxa de sequestro e tempo médio de residência do carbono menor em comparação ao igapó do Rio Abacate, é resultado da alta abundância de espécies pioneiras com longevidade curta, altas taxas de incremento diamétrico e baixa densidade da madeira. A partir dos resultados obtidos não foi possível de associar os distúrbios ocorridos no sistema perturbado às mudanças do regime hidrológico causados pela UHE de Balbina, mas que os igapós da bacia do Rio Uatumã apresentam vários estágios de sucessão secundária possivelmente resultando de distúrbios de condições hidro-climáticas extremas no passado. Baseado nisso, sugerimos mais investigações quanto aos impactos naturais e antropogênicos induzindo mudanças no ciclo hidrológico afetando este ecossistema oligotrófico vulnerável

The Gupta perioperative risk for myocardial infarct or cardiac arrest (MICA) calculator as an intraoperative neurologic deficit predictor in carotid endarterectomy

Background: Patients undergoing carotid endarterectomy (CEA) may experiment intraoperative neurologic deficits (IND) during carotid cross-clamping. This work aimed to assess the impact of the Gupta Perioperative Myocardial Infarct or Cardiac Arrest (MICA) risk calculator in the IND. Methods: From January 2012 to April 2021, patients undergoing CEA with regional anaesthesia for carotid stenosis with IND and consecutively control operated patients without IND were selected. A regressive predictive model was created, and a receiver operating characteristic (ROC) curve was applied for comparison. A multivariable dependence analysis was conducted using a classification and regression tree (CRT) algorithm. Results: A total of 97 out of 194 included patients developed IND. Obesity showed aOR = 4.01 (95% CI: 1.66–9.67) and MICA score aOR = 1.21 (1.03–1.43). Higher contralateral stenosis showed aOR = 1.29 (1.08–1.53). The AUROC curve was 0.656. The CRT algorithm differentiated obese patients with a MICA score ≥ 8. Regarding non-obese patients, the model identified the presence of contralateral stenosis ≥ 55% with a MICA ≥ 10. Conclusion: MICA score might play an additional role in stratifying patients for IND in CEA. Obesity was determined as the best discrimination factor, followed by a score ≥ 8. A higher ipsilateral stenosis degree is suggested to have a part in avoiding procedure-related IND. Larger studies might validate the benefit of MICA score regarding the risk of IND.info:eu-repo/semantics/publishedVersio

Effect of zeolite nanomaterials in methanogenic communities

Recently, the application of zeolite structures in methanogenic communities has attracted significant attention, since they may enhance the anaerobic digestion process, by affecting specifically the methanogenic activity of the sludges1. Zeolites are solid inorganic crystalline materials comprised of silicon, aluminum and oxygen in the three-dimensional structure. The building blocks become arranged in a periodic way to form channels and cages on a nano- and subnanometer scale of strictly regular dimensions, named micropores. The presence of the aluminum in the zeolite framework create a negative charge in the lattice, which can be balanced by the exchangeable cations, as sodium or metal ions.2 In this study, commercial zeolite structures (ZSM5, USY, NaX and NaY) with different particle sizes and different exchangeable cations (Co, Cu, Zn, Fe) were used in order to investigate their effect towards the specific methanogenic activity, both acetoclastic and hydrogenotrophic, of anaerobic sludge. In the acetoclastic methanogenic activity, NaY modified with Cobalt (CoY) decreased the activity in comparison with the control (without zeolite). The remaining zeolites (ZSM5, USY, NaX and NaY), even when modified with metal ions (Zn, Fe, Cu), seems to have no effect on this methanogenic pathway. On the other hand, the hydrogenotrophic methanogenesis was improved by the presence of NaY (109 %), which did not happen in the presence of ZSM5 and USY zeolites. Additionally, the effect of different zeolite concentration was accessed. Overall, the increase of zeolite concentration from 1 g/L to 5 g/L resulted in a higher inhibition towards the methanogenic activity. In addition, the application of these nanomaterials can be evaluated in pure cultures of methanogens, in order to understand and fine-tune the best zeolite nanomaterial concentration that may improve the specific methanogenic activity.We thank the Fundação para a Ciência e Tecnologia (FCT) for financial support through Centre of Chemistry (UID/QUI/00686/2013 and UID/QUI/0686/2016) and BioTecNorte (operation NORTE-01-0145-FEDER-000004), and through Centre of Biological -engineering (UIDB/04469/2020 unit). Cátia S. N. Braga holds a grant SFRH/BD/132003/2017 funded by FCT and European Union (EU), through the Portuguese State Budget and the European Social Fund under the scope of Programa Operacional Regional do Norte.info:eu-repo/semantics/publishedVersio

Human immunodeficiency virus and carotid artery disease – single center experience and literature review

INTRODUCTION: People infected with the human immunodeficiency virus (HIV) - People living with HIV/AIDS (PLWHA) - seem to have an increased risk of incidence and prevalence of cardiovascular diseases, namely stroke of ischemic nature. Additional etiological mechanisms, in addition to aging, appear to lie in chronic virus-mediated inflammation as well as in antiretroviral therapy (ART). The aim of this study was to carry out a retrospective review with descriptive analysis of cases of PLWHA and with a diagnosis of carotid atherosclerotic disease in a tertiary referral center as well as a non-systematic review of the literature. METHODS: All patients diagnosed with HIV infection and concomitantly diagnosed with carotid atherosclerotic disease, in a tertiary center, between October 2007 and December 2019, were selected. A descriptive analysis of the sample and additionally a non-systematic review of the literature using the MEDLINE database, were performed. RESULTS: Nine patients who met the inclusion criteria were selected, 7 (78%) being male. The mean age at diagnosis of carotid disease was 59 years. The diagnosis of HIV infection preceded, on average, 12 years before the diagnosis of carotid disease, while the start of ART preceded this diagnosis by about 11 years. The most common cardiovascular risk factors are dyslipidemia (89%), high blood pressure (56%) and smoking (56%). Approximately 33% had peripheral arterial disease and 22% had coronary artery disease. Only two (22%) patients underwent carotid endarterectomy over a median follow-up of 5 years, both for asymptomatic stenosis. Since the diagnosis of carotid disease, there have been no major cardiovascular events (stroke or acute myocardial infarction). During follow-up there were two deaths. CONCLUSION: PLWHA have a high prevalence of multisite artery disease, manifesting it at a relatively earlier age compared to the general population. These patients benefit from multidisciplinary follow-up for therapeutic optimization in order to obtain better results. However, larger prospective studies are needed to clarify the results in these patients and to improve the therapeutic approach, particularly in those with concomitant carotid disease

Variabilidade do índice de área foliar em campos naturais e floresta de transição na região Sul do Amazonas

The Leaf Area Index (LAI) has strong influence on ecosystems’ energy and mass exchange and is fundamental to the understanding of regional climate changes and ecosystem dynamics. The main goal of this work was to establish, based on geostatistical analyses, the variability and spatial dependence of LAI in the natural fields and transitional forest in southern Amazonas State, in Brazil. The LAI was measured in a regular grid with 33 points at each studied area. Field measurements were done using the canopy analyser LAI -2000, which calculates the structure of the vegetation based on the radiation beneath the tree canopy. The average values of LAI varied according to the studied sites: the highest values were found in the transitional forest (4.42 m2m-2), followed by the high (2.03 m2m-2) and low (1.72 m2m-2) natural fields. All studied sites showed spatial dependence according to the kriging methods, but with different degrees of dependence: spatial dependence was moderate at the transition forest and weak at the natural fields. In the more arboreal open fiel d, the maximum limit at which the points are correlated reached a distance of 35.3 m. The kriging maps proved to be very important tools for describing the spatial distribution of LAI in the Amazon. © 2015, Institute for Environmental Research in Hydrographic Basins (IPABHi). All rights reserved

The shadow of the Balbina dam: A synthesis of over 35 years of downstream impacts on floodplain forests in Central Amazonia

1. The Balbina hydropower dam in the Central Amazon basin, established in the Uatumã River in the 1980s, is emblematic for its socio‐environmental disaster. Its environmental impacts go far beyond the reservoir and dam, however, affecting the floodplain forests (igapó) in the downstream area (dam shadow), which have been assessed using a transdisciplinary research approach, synthesized in this review. 2. Floodplain tree species are adapted to a regular and predictable flood pulse, with high‐ and low‐water periods occurring during the year. This was severely affected by the operation of the Balbina dam, which caused the suppression of both the aquatic phase at higher floodplain elevations and the terrestrial phase at lower floodplain elevations (termed the ‘sandwich effect’). 3. During the period of construction and reservoir fill, large‐scale mortality already occurred in the floodplains of the dam shadow as a result of reduced stream flow, in synergy with severe drought conditions induced by El Niño events, causing hydraulic failure and making floodplains vulnerable to wildfires. 4. During the operational period of the dam, permanent flooding conditions at low topographical elevations resulted in massive tree mortality. So far, 12% of the igapó forests have died along a downstream river stretch of more than 125 km. As a result of flood suppression at the highest elevations, an encroachment of secondary tree species from upland (terra firme) forests occurred. 5. More than 35 years after the implementation of the Balbina dam, the downstream impacts caused massive losses of macrohabitats, ecosystem services, and diversity of flood‐adapted tree species, probably cascading down to the entire food web, which must be considered in conservation management. 6. These findings are discussed critically, emphasizing the urgent need for the Brazilian environmental regulatory agencies to incorporate downstream impacts in the environmental assessments of several dam projects planned for the Amazon region.Additional co-authors: Flávia Machado Durgante, Aline Lopes, Susan E. Trumbore, Hans ter Steege, Adalberto Luis Val, Wolfgang J. Junk, Maria Teresa Fernandez Piedad

Manejo cirúrgico do traumatismo de face: a reconstrução facial no contexto médico

The aim of this study is to disassemble, through scientific articles and government exposure, the surgical management of facial trauma. And as secondary objectives, to understand the particularities of these injuries and understand the effects that oral and maxillofacial trauma entails in the lives of those affected. An in-depth search of articles was carried out in the Scientific Electronic Library Online (SciELO) and PubMed databases, with the following Health Sciences Descriptors (DeCS): Reconstructive surgery; Lesion; Trauma. Articles were selected between the periods of 2000 to 2020, in English and Portuguese. It is concluded from the analysis of these studies that the complexity of the injuries caused by facial trauma can affect the treatment of those affected. Young people are the main victims of facial trauma, which, in turn, affects the aesthetics and psychological condition of those affected. For the best prognosis, the etiological agent, time of exposure of the lesion and the degree of contamination must be considered, in addition to the primordial need, the guarantee of airways.El objetivo de este estudio es desmontar, a través de artículos científicos y exposición gubernamental, el manejo quirúrgico del traumatismo facial. Y como objetivos secundarios, comprender las particularidades de estas lesiones y comprender los efectos que conllevan los traumatismos bucales y maxilofaciales en la vida de los afectados. Se realizó una búsqueda exhaustiva de artículos en las bases de datos Scientific Electronic Library Online (SciELO) y PubMed, con los siguientes Descriptores en Ciencias de la Salud (DeCS): Cirugía reconstructiva; Lesión; Trauma. Los artículos fueron seleccionados entre los períodos de 2000 a 2020, en inglés y portugués. Del análisis de estos estudios se concluye que la complejidad de las lesiones causadas por trauma facial puede afectar el tratamiento de los afectados. Los jóvenes son las principales víctimas de los traumatismos faciales, lo que, a su vez, afecta la estética y el estado psíquico de los afectados. Para el mejor pronóstico se debe considerar el agente etiológico, el tiempo de exposición de la lesión y el grado de contaminación, además de la necesidad primordial, la garantía de las vías aéreas.Objetivo desse estudo é desmontar, por meio de artigos científicos e exposição governamentais, o manejo cirúrgico do trauma de face. E como objetivos secundários, compreender as particularidades dessas lesões e entender os efeitos que o traumatismo bucomaxilofacial acarreta na vida dos acometidos.  Foi realizada uma profunda pesquisa de artigos nas bases de dados Scientific Electronic Library Online (SciELO) e PubMed, com os seguintes Descritores em Ciências da Saúde (DeCS): Cirurgia de reconstrução; Lesão; Trauma. Foram selecionados artigos entre os períodos de 2000 a 2020, nos idiomas Inglês e Português. Conclui-se com a análise desses estudos que, a complexidade das lesões, causadas por um trauma facial, podem afetar a terapêutica dos acometidos. Os jovens são as principais vítimas do trauma facial, que, por sua vez, afeta a estética e a condição psicológica dos acometidos. Para o melhor prognóstico, o agente etiológico, tempo de exposição da lesão e o grau de contaminação devem ser considerados, além da primordial necessidade, a garantia das vias áreas

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio