127 research outputs found
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Eurycea tridentifera
Number of Pages: 2Integrative BiologyGeological Science
A single species of mangrove monitor (Varanus) occupies Ambon, Seram, Buru and Saparua, Moluccas, Indonesia
According to current literature the islands of the central Moluccan region harbor at least three species of monitor lizards. This suggests similar patterns of species richness to the northern Moluccas and could imply significant taxonomic and ecological complexity throughout the Moluccan region. Field investigations in habitats from sea level up to 300 m elevation failed to locate more than one widespread species, by definition referable to Varanus indicus (type locality Ambon). Reassessments of records for other species of mangrove monitors show that these can either be attributed to taxonomic mis-identifications or to colonial-era specimens lacking reliable collection data. We test Principal Components Analysis of scalation characters as a diagnostic tool for some of the island populations and species within the Varanus indicus group.</p
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Usefulness of gene expression profiling of bronchoalveolar lavage cells in acute lung allograft rejection.
BackgroundChronic lung allograft dysfunction (CLAD) is the main limitation to long-term survival after lung transplantation. Because effective therapies are lacking, early identification and mitigation of risk factors is a pragmatic approach to improve outcomes. Acute cellular rejection (ACR) is the most pervasive risk factor for CLAD, but diagnosis requires transbronchial biopsy, which carries risks. We hypothesized that gene expression in the bronchoalveolar lavage (BAL) cell pellet (CP) could replace biopsy and inform on mechanisms of CLAD.MethodsWe performed RNA sequencing on BAL CPs from 219 lung transplant recipients with A-grade ACR (n = 61), lymphocytic bronchiolitis (n = 58), infection (n = 41), or no rejection/infection (n = 59). Differential gene expression was based on absolute fold difference >2.0 and Benjamini-adjusted p-value ≤0.05. We used the Database for Annotation, Visualization and Integrated Discovery Bioinformatics Resource for pathway analyses. For classifier modeling, samples were randomly split into training (n = 154) and testing sets (n = 65). A logistic regression model using recursive feature elimination and 5-fold cross-validation was trained to optimize area under the curve (AUC).ResultsDifferential gene expression identified 72 genes. Enriched pathways included T-cell receptor signaling, natural killer cell-mediated cytotoxicity, and cytokine-cytokine receptor interaction. A 4-gene model (AUC = 0.72) and classification threshold defined in the training set exhibited fair performance in the testing set; accuracy was 76%, specificity 82%, and sensitivity 60%. In addition, classification as ACR was associated with worse CLAD-free survival (hazard ratio = 2.42; 95% confidence interval = 1.29-4.53).ConclusionsBAL CP gene expression during ACR is enriched for immune response pathways and shows promise as a diagnostic tool for ACR, especially ACR that is a precursor of CLAD
The SAMI Galaxy Survey: mass-kinematics scaling relations
We use data from the Sydney-AAO Multi-object Integral-field spectroscopy
(SAMI) Galaxy Survey to study the dynamical scaling relation between galaxy
stellar mass and the general kinematic parameter that combines rotation velocity and velocity dispersion
. We show that the relation: (1)~is linear above
limits set by properties of the samples and observations; (2)~has slightly
different slope when derived from stellar or gas kinematic measurements;
(3)~applies to both early-type and late-type galaxies and has smaller scatter
than either the Tully-Fisher relation () for late
types or the Faber-Jackson relation () for early types;
and (4)~has scatter that is only weakly sensitive to the value of , with
minimum scatter for in the range 0.4 and 0.7. We compare to the
aperture second moment (the `aperture velocity dispersion') measured from the
integrated spectrum within a 3-arcsecond radius aperture
(). We find that while and
are in general tightly correlated, the relation has less scatter than the relation.Comment: 14 pages, 8 figures, Accepted 2019 May 22. Received 2019 May 18; in
original form 2019 January
The SAMI Galaxy Survey: Decomposed Stellar Kinematics of Galaxy Bulges and Disks
We investigate the stellar kinematics of the bulge and disk components in 826
galaxies with a wide range of morphology from the Sydney-AAO Multi-object
Integral-field spectroscopy (SAMI) Galaxy Survey. The spatially-resolved
rotation velocity (V) and velocity dispersion () of bulge and disk
components have been simultaneously estimated using the penalized pixel fitting
(pPXF) method with photometrically defined weights for the two components. We
introduce a new subroutine of pPXF for dealing with degeneracy in the
solutions. We show that the V and distributions in each galaxy can be
reconstructed using the kinematics and weights of the bulge and disk
components. The combination of two distinct components provides a consistent
description of the major kinematic features of galaxies over a wide range of
morphological types. We present Tully-Fisher and Faber-Jackson relations
showing that the galaxy stellar mass scales with both V and for both
components of all galaxy types. We find a tight Faber-Jackson relation even for
the disk component. We show that the bulge and disk components are
kinematically distinct: (1) the two components show scaling relations with
similar slopes, but different intercepts; (2) the spin parameter
indicates bulges are pressure-dominated systems and disks are supported by
rotation; (3) the bulge and disk components have, respectively, low and high
values in intrinsic ellipticity. Our findings suggest that the relative
contributions of the two components explain, at least to first order, the
complex kinematic behaviour of galaxies.Comment: 22 pages, 21 figures; Accepted for publication in MNRA
The SAMI galaxy survey: Can we trust aperture corrections to predict star formation?
In the low-redshift Universe (z < 0.3), our view of galaxy evolution is primarily based on fibre optic spectroscopy surveys. Elaborate methods have been developed to address aperture effects when fixed aperture sizes only probe the inner regions for galaxies of ever decreasing redshift or increasing physical size. These aperture corrections rely on assumptions about the physical properties of galaxies. The adequacy of these aperture corrections can be tested with integral-field spectroscopic data. We use integral-field spectra drawn from 1212 galaxies observed as part of the SAMI Galaxy Survey to investigate the validity of two aperture correction methods that attempt to estimate a galaxy's total instantaneous star formation rate. We show that biases arise when assuming that instantaneous star formation is traced by broad-band imaging, and when the aperture correction is built only from spectra of the nuclear region of galaxies. These biases may be significant depending on the selection criteria of a survey sample. Understanding the sensitivities of these aperture corrections is essential for correct handling of systematic errors in galaxy evolution studies
Star-gas misalignment in galaxies: I. The properties of galaxies from the Horizon-AGN simulation and comparisons to SAMI
Recent integral field spectroscopy observations have found that about 11% of
galaxies show star-gas misalignment. The misalignment possibly results from
external effects such as gas accretion, interaction with other objects, and
other environmental effects, hence providing clues to these effects. We explore
the properties of misaligned galaxies using Horizon-AGN, a large-volume
cosmological simulation, and compare the result with the result of the
Sydney-AAO Multi-object integral field spectrograph (SAMI) Galaxy Survey.
Horizon-AGN can match the overall misalignment fraction and reproduces the
distribution of misalignment angles found by observations surprisingly closely.
The misalignment fraction is found to be highly correlated with galaxy
morphology both in observations and in the simulation: early-type galaxies are
substantially more frequently misaligned than late-type galaxies. The gas
fraction is another important factor associated with misalignment in the sense
that misalignment increases with decreasing gas fraction. However, there is a
significant discrepancy between the SAMI and Horizon-AGN data in the
misalignment fraction for the galaxies in dense (cluster) environments. We
discuss possible origins of misalignment and disagreement.Comment: 23 pages with 15 figures. Accepted for publication in Ap
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