Efeito do teor de ferro na microestrutura e nas propriedades mecânicas de ligas Al-Si-Cu-Mg variando a taxa de resfriamento

Aluminum is the metal of modern life. Heat-treatable aluminum alloys currently occupy a prominent place in the industrial sector and with even greater prospects for use in the future. The A356 alloy is extended to automotive, aerospace and other industrial areas due to its excellent properties, including high strength, low density and excellent castability. Aiming at production cost benefits, less energy consumption and elimination of environmental damage associated with the mining and refining sectors, the recycling of aluminum alloys has been widely explored. In recycled foundry alloys, iron is the main impurity found and, due to its low solubility in aluminum, its presence leads to the formation of second phases, such as β - Al5FeSi intermetallic compounds which are presented in the form of thin and long platelets (needles ) which have a fragile character, degrading the strength and ductility of the alloy, as they act as stress concentrators. The size of the β - Al5FeSi phase needles increases the higher the iron content in the alloy and the lower the cooling rate. Thus, optimal control of iron concentration in foundry alloys is essential. In order to evaluate the effect of iron content on the microstructure and mechanical properties of the A356 alloy, the alloy was cast, containing 1% and 3% iron in its composition and then heat treated. The microstructure after remelting and solidification presents intermetallic phases with acicular morphology of the AlSiMgFe and AlFeSi composition. On the other hand, the microstructure after heat treatment presents intermetallic phases in needle shapes with β -Al5FeSi composition. The additions of iron resulted in a decrease in the cooling rate. It was found that as the iron content increases, there is a reduction in the distribution of the volume fraction of precipitates and an increase in grain size. It is also verified that with different cooling rates, the volume fraction changes, concluding that the higher the cooling rate, the greater the volume fraction. After performing the microhardness test for post-remelting, it was possible to notice an increase in the values of alloys with iron contents. The microhardness values in relation to the cooling rates used in quenching were unexpected. The recycling simulation of this work and consequent iron contamination in the A356 alloy generated changes in the solidification sequence, enabling the appearance of primary phases formed of iron before the crystallization of aluminum grains.O alumínio é verdadeiramente o metal da vida moderna. Ligas de alumínio tratáveis termicamente envolvem atualmente um lugar de destaque no setor industrial e com perspectivas ainda maiores de utilização no futuro. A liga A356 é amplamente utilizada nas áreas automotiva, aeroespacial e outras áreas industriais devido às suas excelentes propriedades, incluindo alta resistência, baixa densidade e excelente capacidade de fundição. Visando benefícios em custo de produção, menos consumo de energia e eliminação de danos ambientais associados aos setores de mineração e refino, a reciclagem de ligas de alumínio têm sido muito explorada. Nas ligas de fundição recicladas, o ferro é a principal impureza encontrada e, devido à sua baixa solubilidade no alumínio, sua presença leva a formação de segundas fases, como compostos intermetálicos β - Al5FeSi que se apresentam-se na forma de plaquetas finas e longas (agulhas) que possuem caráter frágil, degradando a resistência e ductilidade da liga, pois atuam como concentradores de tensões. O tamanho das agulhas da fase β - Al5FeSi aumentam quanto maior o teor de ferro na liga e menor a taxa de resfriamento. Assim, o controle ideal da concentração de ferro nas ligas de fundição é essencial. Com o objetivo de avaliar o efeito do teor de ferro na microestrutura e nas propriedades mecânicas da liga A356 foi realizado a fundição da liga contendo em sua composição 1% e 3% de ferro e depois foram tratadas termicamente. A microestrutura após refusão e solidificação apresentou fases intermetálicas com morfologia acicular da composição AlSiMgFe e AlFeSi. Já a microestrutura após tratamento térmico apresentou fases intermetálicas em formas de agulhas de composição β - Al5FeSi. As adições de ferro resultaram na diminuição da taxa de resfriamento. Foi constatado que a medida que o teor de ferro aumenta, verifica-se uma redução na distribuição da fração volumétrica dos precipitados e um aumento no tamanho de grão. Constata-se também que com diferentes taxas de resfriamento, a fração volumétrica se altera, concluindo que quanto maior a taxa de resfriamento, maior a fração volumétrica. A partir da realização do ensaio de microdureza para as amostras pós refusão, foi possível notar um aumento nos valores das ligas com teores de ferro. Os valores de microdureza em relação às taxas de resfriamento utilizadas na têmpera, foram inesperados. A simulação de reciclagem deste trabalho e consequente contaminação do ferro na liga A356 gerou mudanças na sequência de solidificação, possibilitando o surgimento de fases primárias formadas de ferro antes da cristalização dos grãos de alumínio

Universal Screening of SARS-CoV-2 of Oncology Healthcare Workers — a Brazilian experience

The first confirmed case of coronavirus disease 2019 (COVID-19) in Brazil and Latin America was reported on February 26, 2020, in São Paulo. The outbreak of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has placed unprecedented strain on health-care services worldwide. Asymptomatic health-care workers (HCW) are a potential source of SARS-CoV-2 transmission, especially to immunocompromised Oncology patients. Screening of these HCWs may help contain transmission and isolate only those who require it. At Centro de Terapia Oncológica (CTO), an Oncology clinic in Petrópolis, RJ —Brazil, all HCWs were screened for SARS-CoV-2 in order to isolate those who were asymptomatic/symptomatic and positive for the virus. They were all tested through IgM/IgG rapid testing and those who had symptoms were also tested with nasopharyngeal swabs for reverse transcription polymerase chain reaction (RT-PCR) tests besides IgM/IgG reactivity. Amongst the 60 tested employees, 4 were positive for SARS-CoV-2 and were isolated. This method may be useful for health-care services to detect asymptomatic HCW and maintain workers’ and patients’ health, as transmission probability could be reduced while avoiding becoming short-staffed during this time of crisis

Brazilian recommendations on the safety and effectiveness of the yellow fever vaccination in patients with chronic immune-mediated inflammatory diseases

Background: In Brazil, we are facing an alarming epidemic scenario of Yellow fever (YF), which is reaching the most populous areas of the country in unvaccinated people. Vaccination is the only effective tool to prevent YF. In special situations, such as patients with chronic immune-mediated inflammatory diseases (CIMID), undergoing immunosuppressive therapy, as a higher risk of severe adverse events may occur, assessment of the risk-benefit ratio of the yellow fever vaccine (YFV) should be performed on an individual level. Main body of the abstract: Faced with the scarcity of specific orientation on YFV for this special group of patients, the Brazilian Rheumatology Society (BRS) endorsed a project aiming the development of individualized YFV recommendations for patients with CIMID, guided by questions addressed by both medical professionals and patients, followed an internationally validated methodology (GIN-McMaster Guideline Development). Firstly, a systematic review was carried out and an expert panel formed to take part of the decision process, comprising BRS clinical practitioners, as well as individuals from the Brazilian Dermatology Society (BDS), Brazilian Inflammatory Bowel Diseases Study Group (GEDIIB), and specialists on infectious diseases and vaccination (from Tropical Medicine, Infectious Diseases and Immunizations National Societies); in addition, two representatives of patient groups were included as members of the panel. When the quality of the evidence was low or there was a lack of evidence to determine the recommendations, the decisions were based on the expert opinion panel and a Delphi approach was performed. A recommendation was accepted upon achieving ≥80% agreement among the panel, including the patient representatives. As a result, eight recommendations were developed regarding the safety of YFV in patients with CIMID, considering the immunosuppression degree conferred by the treatment used. It was not possible to establish recommendations on the effectiveness of YFV in these patients as there is no consistent evidence to support these recommendations. Conclusion: This paper approaches a real need, assessed by clinicians and patient care groups, to address specific questions on the management of YFV in patients with CIMID living or traveling to YF endemic areas, involving specialists from many areas together with patients, and might have global applicability, contributing to and supporting vaccination practices. We recommended a shared decision-making approach on taking or not the YFV

2 nd Brazilian Consensus on Chagas Disease, 2015

Abstract Chagas disease is a neglected chronic condition with a high burden of morbidity and mortality. It has considerable psychological, social, and economic impacts. The disease represents a significant public health issue in Brazil, with different regional patterns. This document presents the evidence that resulted in the Brazilian Consensus on Chagas Disease. The objective was to review and standardize strategies for diagnosis, treatment, prevention, and control of Chagas disease in the country, based on the available scientific evidence. The consensus is based on the articulation and strategic contribution of renowned Brazilian experts with knowledge and experience on various aspects of the disease. It is the result of a close collaboration between the Brazilian Society of Tropical Medicine and the Ministry of Health. It is hoped that this document will strengthen the development of integrated actions against Chagas disease in the country, focusing on epidemiology, management, comprehensive care (including families and communities), communication, information, education, and research

Evenness mediates the global relationship between forest productivity and richness

1. Biodiversity is an important component of natural ecosystems, with higher species richness often correlating with an increase in ecosystem productivity. Yet, this relationship varies substantially across environments, typically becoming less pronounced at high levels of species richness. However, species richness alone cannot reflect all important properties of a community, including community evenness, which may mediate the relationship between biodiversity and productivity. If the evenness of a community correlates negatively with richness across forests globally, then a greater number of species may not always increase overall diversity and productivity of the system. Theoretical work and local empirical studies have shown that the effect of evenness on ecosystem functioning may be especially strong at high richness levels, yet the consistency of this remains untested at a global scale. 2. Here, we used a dataset of forests from across the globe, which includes composition, biomass accumulation and net primary productivity, to explore whether productivity correlates with community evenness and richness in a way that evenness appears to buffer the effect of richness. Specifically, we evaluated whether low levels of evenness in speciose communities correlate with the attenuation of the richness–productivity relationship. 3. We found that tree species richness and evenness are negatively correlated across forests globally, with highly speciose forests typically comprising a few dominant and many rare species. Furthermore, we found that the correlation between diversity and productivity changes with evenness: at low richness, uneven communities are more productive, while at high richness, even communities are more productive. 4. Synthesis. Collectively, these results demonstrate that evenness is an integral component of the relationship between biodiversity and productivity, and that the attenuating effect of richness on forest productivity might be partly explained by low evenness in speciose communities. Productivity generally increases with species richness, until reduced evenness limits the overall increases in community diversity. Our research suggests that evenness is a fundamental component of biodiversity–ecosystem function relationships, and is of critical importance for guiding conservation and sustainable ecosystem management decisions

The global biogeography of tree leaf form and habit

Understanding what controls global leaf type variation in trees is crucial for comprehending their role in terrestrial ecosystems, including carbon, water and nutrient dynamics. Yet our understanding of the factors influencing forest leaf types remains incomplete, leaving us uncertain about the global proportions of needle-leaved, broadleaved, evergreen and deciduous trees. To address these gaps, we conducted a global, ground-sourced assessment of forest leaf-type variation by integrating forest inventory data with comprehensive leaf form (broadleaf vs needle-leaf) and habit (evergreen vs deciduous) records. We found that global variation in leaf habit is primarily driven by isothermality and soil characteristics, while leaf form is predominantly driven by temperature. Given these relationships, we estimate that 38% of global tree individuals are needle-leaved evergreen, 29% are broadleaved evergreen, 27% are broadleaved deciduous and 5% are needle-leaved deciduous. The aboveground biomass distribution among these tree types is approximately 21% (126.4 Gt), 54% (335.7 Gt), 22% (136.2 Gt) and 3% (18.7 Gt), respectively. We further project that, depending on future emissions pathways, 17-34% of forested areas will experience climate conditions by the end of the century that currently support a different forest type, highlighting the intensification of climatic stress on existing forests. By quantifying the distribution of tree leaf types and their corresponding biomass, and identifying regions where climate change will exert greatest pressure on current leaf types, our results can help improve predictions of future terrestrial ecosystem functioning and carbon cycling

Native diversity buffers against severity of non-native tree invasions

Determining the drivers of non-native plant invasions is critical for managing native ecosystems and limiting the spread of invasive species1,2. Tree invasions in particular have been relatively overlooked, even though they have the potential to transform ecosystems and economies3,4. Here, leveraging global tree databases5-7, we explore how the phylogenetic and functional diversity of native tree communities, human pressure and the environment influence the establishment of non-native tree species and the subsequent invasion severity. We find that anthropogenic factors are key to predicting whether a location is invaded, but that invasion severity is underpinned by native diversity, with higher diversity predicting lower invasion severity. Temperature and precipitation emerge as strong predictors of invasion strategy, with non-native species invading successfully when they are similar to the native community in cold or dry extremes. Yet, despite the influence of these ecological forces in determining invasion strategy, we find evidence that these patterns can be obscured by human activity, with lower ecological signal in areas with higher proximity to shipping ports. Our global perspective of non-native tree invasion highlights that human drivers influence non-native tree presence, and that native phylogenetic and functional diversity have a critical role in the establishment and spread of subsequent invasions

ATLANTIC EPIPHYTES: a data set of vascular and non-vascular epiphyte plants and lichens from the Atlantic Forest

Epiphytes are hyper-diverse and one of the frequently undervalued life forms in plant surveys and biodiversity inventories. Epiphytes of the Atlantic Forest, one of the most endangered ecosystems in the world, have high endemism and radiated recently in the Pliocene. We aimed to (1) compile an extensive Atlantic Forest data set on vascular, non-vascular plants (including hemiepiphytes), and lichen epiphyte species occurrence and abundance; (2) describe the epiphyte distribution in the Atlantic Forest, in order to indicate future sampling efforts. Our work presents the first epiphyte data set with information on abundance and occurrence of epiphyte phorophyte species. All data compiled here come from three main sources provided by the authors: published sources (comprising peer-reviewed articles, books, and theses), unpublished data, and herbarium data. We compiled a data set composed of 2,095 species, from 89,270 holo/hemiepiphyte records, in the Atlantic Forest of Brazil, Argentina, Paraguay, and Uruguay, recorded from 1824 to early 2018. Most of the records were from qualitative data (occurrence only, 88%), well distributed throughout the Atlantic Forest. For quantitative records, the most common sampling method was individual trees (71%), followed by plot sampling (19%), and transect sampling (10%). Angiosperms (81%) were the most frequently registered group, and Bromeliaceae and Orchidaceae were the families with the greatest number of records (27,272 and 21,945, respectively). Ferns and Lycophytes presented fewer records than Angiosperms, and Polypodiaceae were the most recorded family, and more concentrated in the Southern and Southeastern regions. Data on non-vascular plants and lichens were scarce, with a few disjunct records concentrated in the Northeastern region of the Atlantic Forest. For all non-vascular plant records, Lejeuneaceae, a family of liverworts, was the most recorded family. We hope that our effort to organize scattered epiphyte data help advance the knowledge of epiphyte ecology, as well as our understanding of macroecological and biogeographical patterns in the Atlantic Forest. No copyright restrictions are associated with the data set. Please cite this Ecology Data Paper if the data are used in publication and teaching events. © 2019 The Authors. Ecology © 2019 The Ecological Society of Americ

An embedding technique to determine ττ backgrounds in proton-proton collision data

An embedding technique is presented to estimate standard model tau tau backgrounds from data with minimal simulation input. In the data, the muons are removed from reconstructed mu mu events and replaced with simulated tau leptons with the same kinematic properties. In this way, a set of hybrid events is obtained that does not rely on simulation except for the decay of the tau leptons. The challenges in describing the underlying event or the production of associated jets in the simulation are avoided. The technique described in this paper was developed for CMS. Its validation and the inherent uncertainties are also discussed. The demonstration of the performance of the technique is based on a sample of proton-proton collisions collected by CMS in 2017 at root s = 13 TeV corresponding to an integrated luminosity of 41.5 fb(-1).Peer reviewe