121 research outputs found
The first 62 AGN observed with SDSS-IV MaNGA - IV: gas excitation and star-formation rate distributions
We present maps of the ionized gas flux distributions, excitation,
star-formation rate SFR, surface mass density , and obtain total
values of SFR and ionized gas masses {\it M} for 62 Active Galactic Nuclei
(AGN) observed with SDSS-IV MaNGA and compare them with those of a control
sample of 112 non-active galaxies. The most luminous AGN -- with
L(\rm{[OIII]}\lambda 5007) \ge 3.8\times 10^{40}\,\mbox{erg}\,\mbox{s}^{-1},
and those hosted by earlier-type galaxies are dominated by Seyfert excitation
within 0.2 effective radius from the nucleus, surrounded by LINER
excitation or transition regions, while the less luminous and hosted by
later-type galaxies show equally frequent LINER and Seyfert excitation within
. The extent of the region ionized by the AGN follows the
relation -- as in the case of the Broad-Line
Region. The SFR distribution over the region ionized by hot stars is similar
for AGN and controls, while the integrated SFR -- in the range
\,M\,yr is also similar for the late-type
sub-sample, but higher in the AGN for 75\% of the early-type sub-sample. We
thus conclude that there is no signature of AGN quenching star formation in the
body of the galaxy in our sample. We also find that 66\% of the AGN have higher
ionized gas masses than the controls -- in the range
10\,M -- while 75\% of the AGN have higher
within than the control galaxies
Gas phase metallicity determinations in nearby AGNs with SDSS-IV MaNGA: evidence of metal poor accretion
We derive the metallicity (traced by the O/H abundance) of the Narrow Line
Region ( NLR) of 108 Seyfert galaxies as well as radial metallicity gradients
along their galaxy disks and of these of a matched control sample of no active
galaxies. In view of that, observational data from the SDSS-IV MaNGA survey and
strong emission-line calibrations taken from the literature were considered.
The metallicity obtained for the NLRs %each Active Galactic Nucleus (AGN) was
compared to the value derived from the extrapolation of the radial oxygen
abundance gradient, obtained from \ion{H}{ii} region estimates along the galaxy
disk, to the central part of the host galaxies. We find that, for most of the
objects (), the NLR metallicity is lower than the extrapolated
value, with the average difference ( is due to the accretion of metal-poor
gas to the AGN that feeds the nuclear supermassive black hole (SMBH), which is
drawn from a reservoir molecular and/or neutral hydrogen around the SMBH.
Additionally, we look for correlations between and the electron density
(), [\ion{O}{iii}]5007 and H luminosities,
extinction coefficient ( of the NLRs, as well as the stellar mass
() of the host galaxies. Evidences of an inverse correlation between the
and the parameters , and were found
Population structure, phylogeography, and genetic diversity of the common bottlenose dolphin in the tropical and subtropical southwestern Atlantic Ocean
Cross-cultural adaptation of the Caregiver Reaction Assessment for use in Brazil with informal caregivers of the elderly
This study aimed to carry out the cross-cultural adaptation of the Caregiver Reaction Assessment CRA for use in Brazil with informal caregivers of dependent elderly METHOD A methodological study, of five steps: initial translation, synthesis of translations, retro-translation, evaluation by a judge committee and a pre-test, with 30 informal caregivers of older persons in Fortaleza, Brazil. Content validity was assessed by five experts in gerontology and geriatrics. The cross-cultural adaptation was rigorously conducted, allowing for inferring credibility. RESULTS The Brazilian version of the CRA had a simple and fast application (ten minutes), easily understood by the target audience. It is semantically, idiomatically, experimentally and conceptually equivalent to the original version, with valid content to assess the burden of informal caregivers for the elderly (Content Validity Index = 0.883). CONCLUSION It is necessary that other psychometric properties of validity and reliability are tested before using in care practice and research
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
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
Geographic patterns of tree dispersal modes in Amazonia and their ecological correlates
Aim: To investigate the geographic patterns and ecological correlates in the geographic distribution of the most common tree dispersal modes in Amazonia (endozoochory, synzoochory, anemochory and hydrochory). We examined if the proportional abundance of these dispersal modes could be explained by the availability of dispersal agents (disperser-availability hypothesis) and/or the availability of resources for constructing zoochorous fruits (resource-availability hypothesis).
Time period: Tree-inventory plots established between 1934 and 2019.
Major taxa studied: Trees with a diameter at breast height (DBH) ≥ 9.55 cm.
Location: Amazonia, here defined as the lowland rain forests of the Amazon River basin and the Guiana Shield.
Methods: We assigned dispersal modes to a total of 5433 species and morphospecies within 1877 tree-inventory plots across terra-firme, seasonally flooded, and permanently flooded forests. We investigated geographic patterns in the proportional abundance of dispersal modes. We performed an abundance-weighted mean pairwise distance (MPD) test and fit generalized linear models (GLMs) to explain the geographic distribution of dispersal modes.
Results: Anemochory was significantly, positively associated with mean annual wind speed, and hydrochory was significantly higher in flooded forests. Dispersal modes did not consistently show significant associations with the availability of resources for constructing zoochorous fruits. A lower dissimilarity in dispersal modes, resulting from a higher dominance of endozoochory, occurred in terra-firme forests (excluding podzols) compared to flooded forests.
Main conclusions: The disperser-availability hypothesis was well supported for abiotic dispersal modes (anemochory and hydrochory). The availability of resources for constructing zoochorous fruits seems an unlikely explanation for the distribution of dispersal modes in Amazonia. The association between frugivores and the proportional abundance of zoochory requires further research, as tree recruitment not only depends on dispersal vectors but also on conditions that favour or limit seedling recruitment across forest types
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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