90 research outputs found
Design of a carbon capture system for oxy-fuel combustion in compression ignition engines with exhaust water recirculation
[EN] The oxy-fuel combustion engine concept with onboard oxygen generation and carbon capture (CC) is studied using as a starting point a baseline oxy-fuel combustion layout coupled to a mixed ionic-electronic conducting membranes for producing oxygen (O2) from the air. A CC system is designed accounting for the flash-out temperatures and the operating pressure of the last CO2 purification step. The proposed engine concept is optimized through the product of useful effective efficiency and engine brake power,which is maximized actuating on the start of injection (SOI) for every assessed gas path layouts. The additional cooling power required by the carbon capture system (CC) is also contemplated . Initially, two approaches are compared when the CC is coupled to the O2 generation unit, including or not an intake cooler. The use of intake cooler yields better engine performance than removing it but increases the cooling power requirements significantly. The extreme results from using or not the intake cooler, indicates that a proper solution could combine both cases, approaching for a different cooling concept. A mixer model is developed to recirculate part of the water condensed in the CC towards the cylinder inlet to lower the intake gas temperature and increase the oxidizer heat capacity ratio. From this layout, an optimum setup for SOI and recirculated water mass flow is found considering the trade-off between additional cooling power and engine performance. Indeed, this case reduces the total ICE additional cooling power required by the exclusive use of an intake cooler by about 27% and improves the engine performance by about 20% in comparison to the lack of intake cooling of the charge flow.This work has been partially supported by Grant PID2021-123351OB-I00 funded by MCIN/AEI/10.13039/501100011033 and, as appropriate, by "ERDF A way of making Europe". In addition, the work has been supported by Grant CIPROM/2021/061 funded by Generalitat Valenciana, Spain. Finally, the Ph.D. candidate Vitor Farias has been funded by Generalitat Valenciana, Spain (GRISOLIAP/2020/078) .Luján, JM.; Arnau Martínez, FJ.; Piqueras, P.; Farias-Da Silva, VH. (2023). Design of a carbon capture system for oxy-fuel combustion in compression ignition engines with exhaust water recirculation. Energy Conversion and Management. 284:1-19. https://doi.org/10.1016/j.enconman.2023.11697911928
Aplicação de sistemas de navegação no trauma bucomaxilofacial: uma revisão de literatura / Application of navigation systems in oral and maxillofacial trauma: a literature review
As fraturas faciais são injúrias comuns e o seu manejo entra em uma das principais áreas de atuação do cirurgião bucomaxilofacial, dentre as quais estão as fraturas do complexo zigomático-orbitário, que em determinados casos podem se tornar bastante desafiadoras até mesmo para cirurgiões experientes. Em meio aos demais métodos de tratamento existentes, a cirurgia guiada por navegação surgiu como uma modalidade promissora. Esta revisão de literatura tem como objetivo mostrar uma visão geral da aplicação dos sistemas de navegação na cirurgia do trauma bucomaxilofacial. Foi realizado um levantamento bibliográfico de 1980 a 2020 na base de dados do PubMed com a inclusão de 66 artigos relacionados com ênfase em fraturas faciais, tendo como principal foco fraturas de órbita. Ao longo dos anos, diversas modalidades de tratamento foram estabelecidas para os traumatismos da região bucomaxilofacial. A partir da evolução dos procedimentos de estereotaxia, do advento da tomografia computadorizada e do planejamento cirúrgico virtual, o manejo das fraturas faciais pôde então ser manipulado com a navegação intraoperatória. Os sistemas de navegação podem ser comparados a um sistema de posicionamento global, popularmente conhecido como GPS, o que permite a sincronização em tempo real da posição dos instrumentais com os exames de imagem da anatomia do paciente durante a operação. Isso possibilita realizar uma cirurgia com maior precisão em comparação com tratamentos tradicionais, além de diminuir as taxas de complicações pós-operatórias. Os resultados apresentados nesta revisão apontam que, em virtude da necessidade de investimentos financeiros associados e uma curva de aprendizado inicial, quando as técnicas são suficientemente dominadas o resultado do tratamento torna-se extremamente favorável
A importância do diagnóstico laboratorial para erradicação da malária: uma revisão de literatura / The importance of laboratory diagnosis for malaria eradication: a literature review
A malária é uma doença causada por parasitas do gênero Plasmodium, sendo transmitida aos humanos pela picada de uma fêmea infectada do mosquito da espécie Anopheles. No Brasil, principalmente na região Amazônica, é um dos principais problemas de saúde pública. Porém, também ocorrem casos de malária em regiões extra-amazônica. A malária é uma das principais causas de mortalidade mundialmente e o diagnóstico precoce e rápido impedem uma maior letalidade. Assim, o objetivo do trabalho é realizar uma revisão de literatura sobre a importância do diagnóstico laboratorial para erradicação da malária. Os artigos utilizados nesta revisão de literatura foram pesquisados nas bases de dados National Library of Medicine (PubMED), Google Acadêmico e Literatura Latino-Americana e do Caribe em Ciências da Saúde (LILACS), sendo publicados entre os anos 2004 e 2021. O laboratório é necessário para o diagnóstico da malária, que começa com a identificação do parasita, através do exame microscópio do sangue que pode ser realizado de dois tipos: esfregaço delgado (distendido) ou espesso (gota espessa), sendo o último o mais utilizado. Ambos os métodos apresentam baixo custo, identificando com facilidade e exatidão a espécie do plasmódio. Além disso, técnicas mais precisas como a Reação de Cadeia em Polimerase (PCR) são utilizadas para a identificação do DNA do Plasmodium circulante, porém essa técnica tem um elevado custo e por isso, não é muito utilizada na rotina de diagnóstico laboratorial dos casos de malária, apenas em centros de pesquisa
O papel da citogenética e da biologia molecular no diagnóstico da Leucemia Mieloide Crônica / The role of cytogenetics and molecular biology in the diagnosis of Chronic Myeloid Leukemia
As leucemias se dividem em dois grupos: mieloide e linfoide, e podem ser agudas ou crônicas. A leucemia mieloide crônica (LMC) é o distúrbio mieloproliferativo mais comum entre as neoplasias crônicas, que se caracteriza pela expansão clonal de células progenitoras hematopoiéticas e se dividem em três fases: crônica, acelerada e blástica. A história desta doença se une ao desenvolvimento das técnicas de análise citogenética em humanos. A LMC foi o primeiro câncer a ser associado a uma alteração cromossômica recorrente, uma translocação recíproca entre os longos braços dos cromossomos 9 e 22 - cromossomo Philadelphia (Ph), dando origem ao gene BCR-ABL. O trabalho tem o objetivo de analisar o papel da citogenética e da biologia molecular para o diagnóstico da Leucemia Mieloide Crônica. Assim, foi realizado um levantamento de publicações através dos bancos de dados científicos: Google Acadêmico, Scielo, National Library of Medicine (PubMED), utilizando as palavras-chave “Citogenética”, “LMC” e “Cromossomo Philadelphia”. Os resultados do trabalho demonstram que o acompanhamento citogenético é de extrema importância para um bom prognostico do paciente com LMC. A citogenética convencional ou molecular é necessária para o diagnóstico da LMC, seja na aspiração de medula ou por técnicas de PCR e FISH para a detecção do cromossomo Philadelphia, além da realização do hemograma que é o primeiro indicador da doença. Portanto, quando ocorre a suspeita da doença em pacientes, o encaminhamento apropriado do mesmo é necessário para um bom prognóstico da doença, havendo uma maior probabilidade de tratamento adequado e eficaz
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Rarity of monodominance in hyperdiverse Amazonian forests.
Tropical forests are known for their high diversity. Yet, forest patches do occur in the tropics where a single tree species is dominant. Such "monodominant" forests are known from all of the main tropical regions. For Amazonia, we sampled the occurrence of monodominance in a massive, basin-wide database of forest-inventory plots from the Amazon Tree Diversity Network (ATDN). Utilizing a simple defining metric of at least half of the trees ≥ 10 cm diameter belonging to one species, we found only a few occurrences of monodominance in Amazonia, and the phenomenon was not significantly linked to previously hypothesized life history traits such wood density, seed mass, ectomycorrhizal associations, or Rhizobium nodulation. In our analysis, coppicing (the formation of sprouts at the base of the tree or on roots) was the only trait significantly linked to monodominance. While at specific locales coppicing or ectomycorrhizal associations may confer a considerable advantage to a tree species and lead to its monodominance, very few species have these traits. Mining of the ATDN dataset suggests that monodominance is quite rare in Amazonia, and may be linked primarily to edaphic factors
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
Geography and ecology shape the phylogenetic composition of Amazonian tree communities
Aim: Amazonia hosts more tree species from numerous evolutionary lineages, both young and ancient, than any other biogeographic region. Previous studies have shown that tree lineages colonized multiple edaphic environments and dispersed widely across Amazonia, leading to a hypothesis, which we test, that lineages should not be strongly associated with either geographic regions or edaphic forest types.
Location: Amazonia.
Taxon: Angiosperms (Magnoliids; Monocots; Eudicots).
Methods: Data for the abundance of 5082 tree species in 1989 plots were combined with a mega-phylogeny. We applied evolutionary ordination to assess how phylogenetic composition varies across Amazonia. We used variation partitioning and Moran\u27s eigenvector maps (MEM) to test and quantify the separate and joint contributions of spatial and environmental variables to explain the phylogenetic composition of plots. We tested the indicator value of lineages for geographic regions and edaphic forest types and mapped associations onto the phylogeny.
Results: In the terra firme and várzea forest types, the phylogenetic composition varies by geographic region, but the igapó and white-sand forest types retain a unique evolutionary signature regardless of region. Overall, we find that soil chemistry, climate and topography explain 24% of the variation in phylogenetic composition, with 79% of that variation being spatially structured (R = 19% overall for combined spatial/environmental effects). The phylogenetic composition also shows substantial spatial patterns not related to the environmental variables we quantified (R = 28%). A greater number of lineages were significant indicators of geographic regions than forest types.
Main Conclusion: Numerous tree lineages, including some ancient ones (>66 Ma), show strong associations with geographic regions and edaphic forest types of Amazonia. This shows that specialization in specific edaphic environments has played a long-standing role in the evolutionary assembly of Amazonian forests. Furthermore, many lineages, even those that have dispersed across Amazonia, dominate within a specific region, likely because of phylogenetically conserved niches for environmental conditions that are prevalent within regions
Geography and ecology shape the phylogenetic composition of Amazonian tree communities
AimAmazonia hosts more tree species from numerous evolutionary lineages, both young and ancient, than any other biogeographic region. Previous studies have shown that tree lineages colonized multiple edaphic environments and dispersed widely across Amazonia, leading to a hypothesis, which we test, that lineages should not be strongly associated with either geographic regions or edaphic forest types.LocationAmazonia.TaxonAngiosperms (Magnoliids; Monocots; Eudicots).MethodsData for the abundance of 5082 tree species in 1989 plots were combined with a mega-phylogeny. We applied evolutionary ordination to assess how phylogenetic composition varies across Amazonia. We used variation partitioning and Moran's eigenvector maps (MEM) to test and quantify the separate and joint contributions of spatial and environmental variables to explain the phylogenetic composition of plots. We tested the indicator value of lineages for geographic regions and edaphic forest types and mapped associations onto the phylogeny.ResultsIn the terra firme and várzea forest types, the phylogenetic composition varies by geographic region, but the igapó and white-sand forest types retain a unique evolutionary signature regardless of region. Overall, we find that soil chemistry, climate and topography explain 24% of the variation in phylogenetic composition, with 79% of that variation being spatially structured (R2 = 19% overall for combined spatial/environmental effects). The phylogenetic composition also shows substantial spatial patterns not related to the environmental variables we quantified (R2 = 28%). A greater number of lineages were significant indicators of geographic regions than forest types.Main ConclusionNumerous tree lineages, including some ancient ones (>66 Ma), show strong associations with geographic regions and edaphic forest types of Amazonia. This shows that specialization in specific edaphic environments has played a long-standing role in the evolutionary assembly of Amazonian forests. Furthermore, many lineages, even those that have dispersed across Amazonia, dominate within a specific region, likely because of phylogenetically conserved niches for environmental conditions that are prevalent within regions
Mapping density, diversity and species-richness of the Amazon tree flora
Using 2.046 botanically-inventoried tree plots across the largest tropical forest on Earth, we mapped tree species-diversity and tree species-richness at 0.1-degree resolution, and investigated drivers for diversity and richness. Using only location, stratified by forest type, as predictor, our spatial model, to the best of our knowledge, provides the most accurate map of tree diversity in Amazonia to date, explaining approximately 70% of the tree diversity and species-richness. Large soil-forest combinations determine a significant percentage of the variation in tree species-richness and tree alpha-diversity in Amazonian forest-plots. We suggest that the size and fragmentation of these systems drive their large-scale diversity patterns and hence local diversity. A model not using location but cumulative water deficit, tree density, and temperature seasonality explains 47% of the tree species-richness in the terra-firme forest in Amazonia. Over large areas across Amazonia, residuals of this relationship are small and poorly spatially structured, suggesting that much of the residual variation may be local. The Guyana Shield area has consistently negative residuals, showing that this area has lower tree species-richness than expected by our models. We provide extensive plot meta-data, including tree density, tree alpha-diversity and tree species-richness results and gridded maps at 0.1-degree resolution
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