784 research outputs found
Patterns of tree species composition and richness across the principal biomes of lowland tropical South America and their underlying environmental drivers
Lowland tropical South America encompasses some of the most species-rich and
threatened ecosystems in the world, spanning across countries such as Brazil, Bolivia,
Colombia, Ecuador, Peru and Venezuela, which are known for their biodiversity.
However, due to its incredible environmental and ecological complexity and that
most of its area has yet to be scientifically studied in any depth, controversy
surrounds its biomes’ identities, the limits of their geographic and environmental
distributions and estimates of their tree species richness. The main objective of this
thesis is to study the phytogeography of lowland Tropical South America by delimiting
its biomes through a floristic approach, by investigating these biomes’ environmental
controls and dynamics and by assessing their tree species richness and endemism. In
order to fulfil this objective, we have employed a dataset of thoroughly checked tree
species checklists, the NeoTropTree (NTT) dataset, which covers more than 8000
locations across South, Central and southern North America and encompasses
occurrence records for more than 12000 tree species.
Firstly, I defined and mapped the main biomes in lowland tropical South America
(LTSA) through the means of a hierarchical clustering analysis based on tree species
composition associated with an a priori classification of 4103 NTT sites into
vegetation types. I then proceeded to map these biomes geographically and to assess
their environmental overlaps (both climatic and edaphic) through a classification tree
approach (random forest analysis). I was able to delimit five main biomes in LTSA:
Amazon Forest, Atlantic Forest, Chaco, Savanna and Seasonally Dry Tropical Forest
(SDTF). I also show that there is an important environmental overlap amongst
biomes. Error rates for site classification into biome using solely environmental data
ranged from 19-21% when only climate was considered and 16-18% when I also took
edaphic variables into account. I conclude that it is viable and advisable to use tree
species composition to determine biome identity, at least within individual
continents. In the case of LTSA, there is high biome heterogeneity at small spatial
scales, which explains why it is so challenging to use climatic and/or interpolation
based edaphic data, or remotely-sensed imagery, to map tropical biomes. Because of
this, I then conclude that biome delimitation using floristic information may enable
more efficient biome conservation and management efforts.
Secondly, I investigated the environmental controls distinguishing biome limits for
two regions of LTSA with high biome heterogeneity – eastern Brazil and Bolivia. To
this end, I selected 182 NTT sites in these two regions, collected detailed soil data
from the field and extracted climate and fire data from publicly available GIS data
layers. I assigned these sites to one of three states based on their tree species
composition: moist forest (including both Atlantic and Amazon Forests), SDTF or
savanna. Selected environmental variables were organized into three distinct
categories describing functional environmental regime: water availability, soil fertility
and fire, and their significance as predictors of biome identity was assessed within a
structural equation modelling framework. I found that environmental controls
behind biome distribution differ between the two studied areas and according to the
biomes involved. I concluded that water availability, soil fertility and fire are all
important determinants of biome limits. Amongst the three categories, water
availability was the most important one in determining biome identity at our study
sites, with soil fertility differentiating eastern Brazil SDTFs from the other biomes, and
fire representing an important determinant of savanna’s environmental limits.
Thirdly, I estimated and compared tree species richness and endemism levels of
LTSA’s main biomes using NTT’s tree species checklists and incidence (i.e.,
occurrence) data. To do so, I extracted tree species information for 4540 sites
registered in NeoTropTree distributed across four biomes: Amazon Forest, Atlantic
Forest, Savanna and SDTF. I first compared how tree species accumulated with
number of sites sampled for biomes and then estimated biomes’ total tree species
richness using non-parametric approaches (species extrapolation curves). I also
estimated the number of endemic tree species to these areas with two approaches:
indicator species analyses and absolute unique/shared species counts. I was able to
show that the Amazon Forest is the most tree species-rich environment in LTSA,
followed by the Atlantic Forest, Savannas and then SDTFs. In relation to endemism
levels, the Amazon and Atlantic Forests’ tree flora are mainly composed of endemic
tree species whereas that is not the case for the savanna and SDTF. The estimation
of total tree species richness through extrapolation curves revealed that around 94%
of the tree flora of the Amazon forest, the Atlantic forest and the SDTF have already
been recorded. According to the same analysis, only around 70% of the savannah tree
flora has been recorded. However, this pattern might be related to the high number
of biome intrusions into this biome. The differences in richness and endemism
between the moist (Amazon and Antlantic forests) and drier biomes (savanna and
SDTF) suggest that drought-sensitivity and biogeographic history are drivers of tree
species distribution in LTSA.
Finally, by integrating biome delimitation based on floristic composition with
knowledge on these environments’ environmental correlates and tree species
richness, I was able to describe LTSA’s main phytogeographic features in a way that
has never been done before, drawing attention to its complexities and performing
novel cross-biome comparisons. My study shows that LTSA’s biomes are interspersed
across geographic space, especially in the Dry Diagonal located between the Amazon
and Atlantic Forests, and that environmental controls driving these ecosystems’
distributions can vary according to the biomes being considered and the geographic
location. I also show that LTSA’s most tree species-rich biomes are the ones with the
highest quantity of endemic tree species and that taxonomic expeditions to the
Amazon Forest can potentially lead to more species being described in these
environments. To summarize, I was able to highlight LTSA’s main floristic patterns
and link them to environmental drivers and tree species richness, thereby
substantially transforming how these biomes are perceived by biodiversity scientists
and conservationists
Dissecting the difference in tree species richness between Africa and South America
peer reviewedSignificanceOur full-scale comparison of Africa and South America's lowland tropical tree floras shows that both Africa and South America's moist and dry tree floras are organized similarly: plant families that are rich in tree species on one continent are also rich in tree species on the other continent, and these patterns hold across moist and dry environments. Moreover, we confirm that there is an important difference in tree species richness between the two continents, which is linked to a few families that are exceptionally diverse in South American moist forests, although dry formations also contribute to this difference. Plant families only present on one of the two continents do not contribute substantially to differences in tree species richness
Phylogenetic regionalization of tree assemblages reveals novel patterns of evolutionary affinities in the Atlantic Forest
peer reviewedAim: We used a phylogenetic approach to group assemblages of woody plant into major vegetation units in the Atlantic Forest, thus for the first time incorporating information on species evolutionary relationships into a bioregionalization of this critical hotspot. A phylogenetic regionalization will provide a spatially explicit framework for answering many basic and applied questions in biogeography, ecology and conservation. Location: Atlantic Forest. Taxon: Angiosperms. Methods: Our data set comprises 614 genera and 116 families, spread over 1,755 assemblages. To place assemblages in a multivariate evolutionary composition space, we used a phylogenetically informed ordination analysis, and to determine what the main phylogenetic groups of assemblages were, we used K-means clustering based on phylogenetic dissimilarity of assemblages. To quantify how well environmental variables distinguish the phylogenetic groups found, we implemented classification tree approaches. Then, to explore the evolutionary turnover between the phylogenetic groups, we calculated phylogenetic beta diversity. Finally, we determined the lineages that are most strongly associated with individual phylogenetic groups using an indicator analysis for lineages. Results: Our analyses suggest that there are seven principal groups, in terms of evolutionary lineage composition, in the Atlantic Forest. The greatest turnover of phylogenetic lineage composition separates tropical evergreen rain forest and semideciduous assemblages from subtropical and highland assemblages. The mixed subtropical forest showed the lowest phylogenetic compositional similarity values with other groups. Tropical rain forest had the highest number of significant indicator lineages, and the highest values of the indicator statistic for lineages. Main conclusions: We found that the most pronounced evolutionary division separates southern and highland tree assemblages from those occurring under more tropical climates and at lower elevations. Our phylogenetic analyses point to an environmentally driven compositional division, likely based on the regular occurrence of freezing versus non-freezing temperatures. Precipitation and edaphic regimes that assemblages experience had less definitive effects on their evolutionary lineage composition
The strengths and weaknesses of species distribution models in biome delimitation
This is the final published version, also available from Frontiers via the DOI in this record.Aim: The aim was to test whether species distribution models (SDMs) can reproduce major macroecological patterns in a species-rich, tropical region and provide recommendations for using SDMs in areas with sparse biotic inventory data. Location: North-east Brazil, including Minas Gerais. Time period: Present. Major taxa studied: Flowering plants. Methods: Species composition estimates derived from stacked SDMs (s-SDMs) were compared with data from 1,506 inventories of 933 woody plant species from north-east Brazil. Both datasets were used in hierarchical clustering analyses to delimit floristic units that correspond to biomes. The ability of s-SDMs to predict the identity, functional composition and floristic composition of biomes was compared across geographical and environmental space. Results: The s-SDMs and inventory data both resolved four major biomes that largely corresponded in terms of their distribution, floristics and function. The s-SDMs proved excellent at identifying broad-scale biomes and their function, but misassigned many individual sites in complex savanna–forest mosaics. Main conclusions: Our results show that s-SDMs have a unique role to play in describing macroecological patterns in areas lacking inventory data and for poorly known taxa. s-SDMs accurately predict floristic and functional macroecological patterns but struggle in areas where non-climatic factors, such as fire or soil, play key roles in governing distributions.Natural Environment Research Council (NERC)Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorConselho Nacional de Desenvolvimento Científico e TecnológicoRoyal Societ
Inserção de egressos de Programas de Residência Multiprofissional no SUS
INTRODUÇÃO: Os Programas de Residência Multiprofissional em Saúde (PRMS) configuram-se como estratégia para a formação de força de trabalho para o Sistema Único de Saúde (SUS). OBJETIVO: Investigar a proporção de egressos de PRMS voltados à Atenção Primária à Saúde (APS) inseridos no SUS e fatores associados. MÉTODOS: Trata-se de um estudo seccional desenvolvido com egressos de PRMS voltados à APS de todo o Brasil, referente ao período de 2015 a 2019. Os participantes responderam a um questionário on-line com informações pessoais gerais, inserção na pós-graduação stricto sensu, no mercado de trabalho e especificamente no SUS. Foram aplicados o teste qui-quadrado de Pearson, para análises bivariadas, e Regressão de Poisson, para a análise múltipla. RESULTADOS: Participaram do estudo 365 egressos de Programas de todas as regiões brasileiras. Destes, 80,2% relataram inserção no mercado de trabalho e 47,9% informaram estar trabalhando no SUS. A inserção no SUS esteve associada às profissões que compõem a Equipe de Referência para a APS (RP = 1,87; IC95% 1,54–2,28) e à não inserção em programas de pós-graduação stricto sensu (RP = 0,77; IC95% 0,61–0,97). Quanto às características de inserção, prevaleceram o cenário da APS (47,4%) e o trabalho voltado à atenção à saúde (84,9%). Quase 40% dos egressos inseridos no SUS estão trabalhando por intermédio de vínculos instáveis, além de frequente não valorização do título da residência no recrutamento (56,9%). Entre os inseridos no SUS, 8,7% relataram terem sido selecionados para o enfrentamento da pandemia de covid-19. CONCLUSÕES: Os resultados deste estudo reforçaram a necessidade de política de incentivo à manutenção, criação e valorização dos PRMS e alertaram para possível aumento da dificuldade de inserção das categorias profissionais, frente ao cenário de desfinanciamento da saúde.INTRODUCTION: The Multiprofessional Health Residency Programs (PRMS) were set up as a strategy for training workforce for the Brazilian Unified Health System (SUS). OBJECTIVE: To investigate the proportion of alumni from Primary Health Care Multiprofessional Residency Programs admitted into the SUS and associated factors. METHODS: This is a sectional study developed with alumni from Primary Health Care Multiprofessional Residency Programs from all over Brazil, encompassing the period from 2015 to 2019. Participants answered an online questionnaire with general personal information, admission into stricto sensu graduate school, the labor market and, specifically, the SUS. We applied Pearson's chi-square test for bivariate analyses and Poisson’s regression for multiple analysis. RESULTS: A total of 365 alumni from Programs from all Brazilian regions participated in the study. Of those, 80.2% reported entry into the labor market and 47.9% reported being employed in the SUS. Admission into the SUS has been associated with the professions that make up the Reference Team for Primary Health Care (PHC) (PR 1.87; 95% CI 1.54–2.28) and non-admission into stricto sensu graduate programs (PR 0.77; 95% CI 0.61–0.97). Regarding admission characteristics, the PHC scenario (47.4%) and work focused on health care (84.9%) were prevalent. Almost 40% of alumni who entered the SUS are working with unstable contracts. Besides, being a residency alumnus is often undervalued in recruitment (56.9%). Among those admitted into the SUS, 8.7% reported being selected to work in the Covid-19 pandemic effort. CONCLUSIONS: The results of this study reinforce the need for a policy to encourage the maintenance, creation and valorization of the PRMS. They also warn about the possibility that admission into the SUS for workers is increasingly difficult due to the current underfunding of the health system
Número ideal de amostras para classificação comercial de cultivares de trigo no Brasil
The objective of this work was to estimate the optimal number of samples for commercial classification of wheat (Triticum aestivum) cultivars for gluten strength average, in the states of Rio Grande do Sul and Paraná, the main wheat producing regions in Brazil. The alveography analysis results of grain samples, from competition assays of three wheat cultivars (up to 280 experiments in 11 years), were used. The optimal number of samples was estimated based on the properties of the mean sampling distribution by adaptation region, in the states of Rio Grande do Sul and Paraná. The optimal number ranged from 13 to 22, 30 to 49, and 121 to 197 samples per state, respectively, for to error margin of 30, 20, and 10 gluten strength units (W), with minimum of 7, 16, and 63 samples per adaptation region and per state for error margin of 30, 20 and 10 W, respectively. The optimal number of samples for commercial classification of wheat cultivars, in the states of Rio Grande do Sul and Paraná, is of at least 13 samples per state and of 7 samples per adaptation region and per state for error margin of 30 W, which are higher values than those used by breeders for classification.O objetivo deste trabalho foi estimar o número ideal de amostras, para a classificação comercial de cultivares de trigo (Triticum aestivum) quanto à média de força de glúten, no Rio Grande do Sul e no Paraná, principais estados produtores de trigo do Brasil. Resultados de análises de alveografia de amostras de grãos, provenientes de ensaios de competição de três cultivares de trigo (até 280 ensaios, em 11 anos), foram utilizados. O número ideal de amostras foi estimado com base nas propriedades da distribuição amostral da média, por região de adaptação, nos estados do Rio Grande do Sul e do Paraná. O número ideal variou de 13 a 22, 30 a 49, e 121 a 197 amostras por estado, respectivamente, para a margem de erro de 30, 20 e 10 unidades de força de glúten (W), com, no mínimo, 7, 16 e 63 amostras por região de adaptação e por estado, para a margem de erro de 30, 20 e 10 W, respectivamente. O número ideal de amostras para a classificação comercial de cultivares de trigo, no Rio Grande do Sul e no Paraná, é no mínimo de 13 amostras, por estado, e 7 de amostras, por região de adaptação e por estado, para a margem de erro de 30 W, valores que são superiores aos utilizados para a classificação pelos obtentores
Internações por neoplasia maligna do colo do útero em Goiás no período de 2008 a 201
Introdução: O câncer do colo do útero é o segundo tumor mais frequente entre as mulheres, segundo o Instituto Nacional de Câncer (INCA). É um câncer que evolui lentamente, dessa forma, é necessário analisar de forma crítica como o fator faixa etária (FE) influencia nas taxas de internações pela neoplasia, a fim de evidenciar, por exemplo, em qual idade a prevalência da doença é maior. Isso porque afeta a incidência e a prevalência das internações. Assim, é imprescindível conhecer de forma objetiva os dados e análises sobre a influência desse fator nas taxas de internações. Objetivo: Avaliar a relação entre a faixa etária e o número de internações por neoplasia maligna do colo do útero em Goiás (GO) no período de jan/2008 a dez/2018, sob uma perspectiva crítica. Material e método: Trata-se de um estudo epidemiológico das séries temporais das taxas de internações por neoplasia maligna do colo do útero entre mulheres em Goiás (GO), no período de jan/2008 a dez/2018. O estudo estratificou as taxas de internações em cinco faixas-etárias: 20 a 29 anos, 30 a 39 anos, 40 a 49 anos, 50 a 59 anos e 60 ou mais anos. Os dados da pesquisa foram obtidos através do Sistema de Internações Hospitalares (SIH) e pela Rede Interagencial de Informações para a Saúde (RIPSA), para estimativas de população. Para a análise de conteúdo dos dados obtidos foi utilizado o método de Prais-Winsten. Resultados: Foram analisadas 6440 internações entre jan/2008 e dez/2018. A FE com maior número de internações foi a de 40 a 49 anos com 2502 (38,8%) e a com menor número foi entre 20 a 29 anos com 262 (4%) internações. A prevalência de mulheres internadas foi de 0,3% e a taxa de óbito foi de 8,63. As taxas de internações a cada 100.000 mulheres, em ordem crescente dos anos analisados, começando em 2008 e terminando em 2018, foram as seguintes: 37,8; 49; 42; 32; 26,6; 19; 18,4; 17,2; 15,8; 19 e 24. Dessa forma, o ano com maior taxa foi 2009 com 49/100.000 mil mulheres e apesar de 2008 ter 37/100.000 e 2018 ter 24/100.000, a tendência temporal da taxa é estacionária (bvalor = - 0,15; p-valor = 0.144). Conclusão: O estudo mostrou que, no estado de Goiás, a FE com o maior índice de internação por CA do colo uterino foi entre 40 e 49 anos e a com menor incidência foi entre 20 e 29 anos. O resultado corrobora com a literatura, pois o câncer do colo de útero é raro em mulheres até 30 anos e o pico de incidência é entre 45 a 50 anos. A diminuição do número de internações ao longo do tempo, com um leve aumento em 2017 e 2018, mas substancialmente menor do que em 2008, pode significar melhoria no rastreio e no manejo dessa doença na atenção básica. Porém, mesmo com uma possível melhora na prevenção, as taxas de internações mostram-se estacionárias, o que nos remete a necessidade de políticas públicas mais eficazes para prevenção e promoção de saúde, principalmente na FE mais acometida
PREVALENCIA DE COMPLICACIONES ASOCIADAS A LA AUSENCIA DEL PRIMER MOLAR EN UNA POBLACIÓN DETERMINADA: ESTUDIO RADIOGRÁFICO
Este estudo avaliou o a frequência das perdas de primeiros molares permanentes de pacientes usuários das clínicas odontológicas de uma instituição pública de ensino superior por radiografias panorâmicas, além de pontuar as principais consequências dessa perda na cavidade bucal. Este foi um estudo retrospectivo de 1.000 radiografias panorâmicas de pacientes atendidos em um curso de Odontologia. A faixa etária foi de 7 a 55 anos e observou-se as consequências relacionadas a perda do primeiro molar permanente. Os resultados revelaram que na amostra estudada o dente mais ausente foi o inferior direito, seguido do inferior esquerdo, superior direito e superior esquerdo. Ainda, as principais consequências da perda do primeiro molar foram mesialização do segundo molar, seguido de migração de dentes anteriores e posteriores, giroversão dos pré-molares, extrusão do antagonista e distalização do segundo pré-molar.This study evaluated the frequency of loss of first permanent molars in patients using dental clinics of a public instituition of higher education through panoramic radiographs, in addition to pointing out the main consequences of this loss in the oral cavity. This was a retrospective study of 1,000 panoramic radiographs of patients seen in a Dentistry course. The age range was from 7 to 55 years and the consequences related to the loss of the first permanent molar were observed. The results revealed that in the studied sample the most absent tooth was the lower right, followed by the lower left, upper right and upper left. Also, the main consequences of the loss of the first molar were mesialization of the second molar, followed by migration of anterior and posterior teeth, rotation of the premolars, extrusion of the antagonist and distalization of the second premolarEste estudo avaliou o a frequência das perdas de primeiros molares permanentes de pacientes usuários das clínicas odontológicas de uma instituição pública de ensino superior por radiografias panorâmicas, além de pontuar as principais consequências dessa perda na cavidade bucal. Este foi um estudo retrospectivo de 1.000 radiografias panorâmicas de pacientes atendidos em um curso de Odontologia. A faixa etária foi de 7 a 55 anos e observou-se as consequências relacionadas a perda do primeiro molar permanente. Os resultados revelaram que na amostra estudada o dente mais ausente foi o inferior direito, seguido do inferior esquerdo, superior direito e superior esquerdo. Ainda, as principais consequências da perda do primeiro molar foram mesialização do segundo molar, seguido de migração de dentes anteriores e posteriores, giroversão dos pré-molares, extrusão do antagonista e distalização do segundo pré-molar.Este estudio evaluó la frecuencia de pérdidas de primeros molares permanentes de pacientes utilizando clínicas dentales de una institución pública de educación superior por radiografías panorámicas, además de puntuar las principales consecuencias de esta pérdida en la cavidad oral. Este fue un estudio retrospectivo de 1.000 radiografías panorámicas de pacientes atendidos en un curso de odontología. El rango de edad fue de 7 a 55 años y se observaron las consecuencias relacionadas con la pérdida del primer molar permanente. Los resultados revelaron que en la muestra estudiada el diente más ausente fue el inferior derecho, seguido del inferior izquierdo, superior derecho y superior izquierdo. Asimismo, las principales consecuencias de la pérdida del primer molar fueron la mesialización del segundo molar, seguida de la migración de los dientes anteriores y posteriores, la giroversión de los premolares, la extrusión del antagonista y la distalización del segundo premolar
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