574 research outputs found

    Evidence of boosted 13CO/12CO ratio in early-type galaxies in dense environments

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    We present observations of 13^{13}CO(1-0) in 17 Combined Array for Research in Millimeter Astronomy (CARMA) Atlas3D early-type galaxies (ETGs), obtained simultaneously with 12^{12}CO(1-0) observations. The 13^{13}CO in six ETGs is sufficiently bright to create images. In these 6 sources, we do not detect any significant radial gradient in the 13^{13}CO/12^{12}CO ratio between the nucleus and the outlying molecular gas. Using the 12^{12}CO channel maps as 3D masks to stack the 13^{13}CO emission, we are able to detect 15/17 galaxies to >3σ>3\sigma (and 12/17 to at least 5σ\sigma) significance in a spatially integrated manner. Overall, ETGs show a wide distribution of 13^{13}CO/12^{12}CO ratios, but Virgo cluster and group galaxies preferentially show a 13^{13}CO/12^{12}CO ratio about 2 times larger than field galaxies, although this could also be due to a mass dependence, or the CO spatial extent (RCO/ReR_{\rm CO}/R_{\rm e}). ETGs whose gas has a morphologically-settled appearance also show boosted 13^{13}CO/12^{12}CO ratios. We hypothesize that this variation could be caused by (i) the extra enrichment of gas from molecular reprocessing occurring in low-mass stars (boosting the abundance of 13^{13}C to 12^{12}C in the absence of external gas accretion), (ii) much higher pressure being exerted on the midplane gas (by the intracluster medium) in the cluster environment than in isolated galaxies, or (iii) all but the densest molecular gas clumps being stripped as the galaxies fall into the cluster. Further observations of 13^{13}CO in dense environments, particularly of spirals, as well as studies of other isotopologues, should be able to distinguish between these hypotheses.Comment: 13 pages, 3 tables, 7 figures, accepted by MNRA

    The HI Tully-Fisher Relation of Early-Type Galaxies

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    We study the HI K-band Tully-Fisher relation and the baryonic Tully-Fisher relation for a sample of 16 early-type galaxies, taken from the ATLAS3D sample, which all have very regular HI disks extending well beyond the optical body (> 5 R_eff). We use the kinematics of these disks to estimate the circular velocity at large radii for these galaxies. We find that the Tully-Fisher relation for our early-type galaxies is offset by about 0.5-0.7 magnitudes from the relation for spiral galaxies. The residuals with respect to the spiral Tully-Fisher relation correlate with estimates of the stellar mass-to-light ratio, suggesting that the offset between the relations is mainly driven by differences in stellar populations. We also observe a small offset between our Tully-Fisher relation with the relation derived for the ATLAS3D sample based on CO data representing the galaxies' inner regions (< 1 R_eff). This indicates that the circular velocities at large radii are systematically 10% lower than those near 0.5-1 R_eff, in line with recent determinations of the shape of the mass profile of early-type galaxies. The baryonic Tully-Fisher relation of our sample is distinctly tighter than the standard one, in particular when using mass-to-light ratios based on dynamical models of the stellar kinematics. We find that the early-type galaxies fall on the spiral baryonic Tully-Fisher relation if one assumes M/L_K = 0.54 M_sun/L_sun for the stellar populations of the spirals, a value similar to that found by recent studies of the dynamics of spiral galaxies. Such a mass-to-light ratio for spiral galaxies would imply that their disks are 60-70% of maximal. Our analysis increases the range of galaxy morphologies for which the baryonic Tully-Fisher relations holds, strengthening previous claims that it is a more fundamental scaling relation than the classical Tully-Fisher relation.Comment: Accepted for publication in Astronomy & Astrophysic

    Comparative full genome sequence analysis of wild-type and chicken embryo origin vaccine-like infectious laryngotracheitis virus field isolates from Canada

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    Infectious laryngotracheitis (ILT), caused by infectious laryngotracheitis virus (ILTV), occurs sporadically in poultry flocks in Canada. Live attenuated chicken embryo origin (CEO) vaccines are being used routinely to prevent and control ILTV infections. However, ILT outbreaks still occur since vaccine strains could revert to virulence in the field. In this study, 7 Canadian ILTV isolates linked to ILT outbreaks across different time in Eastern Canada (Ontario; ON and Quebec; QC) were whole genome sequenced. Phylogenetic analysis confirmed the close relationship between the ON isolates and the CEO vaccines, whereas the QC isolates clustered with strains previously known as CEO revertant and wild-type ILTVs. Recombination network analysis of ILTV sequences revealed clear evidence of historical recombination between ILTV strains circulating in Canada and other geographical regions. The comparison of ON CEO clustered and QC CEO revertant clustered isolates with the LT BlenÂź CEO vaccine reference sequence showed amino acid differences in 5 and 12 open reading frames (ORFs), respectively. Similar analysis revealed amino acid differences in 32 ORFs in QC wild-type isolates. Compared to all CEO vaccine strains in the public domain, the QC wild-type isolates showed 15 unique mutational sites leading to amino acid changes in 13 ORFs. Our outcomes add to the knowledge of the molecular mechanisms behind ILTV genetic variance and provide genetic markers between wild-type and vaccine strains

    Methotrexate versus expectant management for treatment of tubal ectopic pregnancy : An individual participant data meta-analysis

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    ACKNOWLEDGMENTSThe authors thank Amsterdam University Medical Center, Amsterdam, Netherlands, King's College Hospital, London, UK and the authors of the original studies for their collaboration and provision of IPD.Peer reviewedPublisher PD

    Predicting flood hazard indices in torrential or flashy river basins and catchments

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    Flood hazard maps are one of the main components of any flood risk management strategy. It is predicted that the degree of flood risk is going to significantly increase in the future due to climatic and environmental changes, and hence it is increasingly important that state-of-the-art methods are implemented for assessing human stability in floodwaters. Therefore, this paper focuses on proposing more accurate and detailed guidelines for predicting flood hazard indices in small and steep river basins or catchments, prone to the occurrence of flash flooding. The results obtained in this study indicate that for river basins with an average bed gradient greater than 1% (i.e. torrential or flashy river basins or catchments), then the flood hazard indices should be predicted using criteria which are based on the physical interpretation of the processes that affect the human stability in floodwaters, i.e. mechanics based and experimentally calibrated flood hazard assessment methods

    Urban deciduous tree leaves as biomonitors of trace element (As, V and Cd) atmospheric pollution in Belgrade, Serbia

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    Leaves of common deciduous trees: horse chestnut (Aesculus hippocastanum) and linden (Tilia spp.) from three parks within the urban area of Belgrade were studied as biomonitors of trace element (As, V, and Cd) atmospheric pollution. The May–September trace element accumulation in the leaves, and their temporal trends, were assayed in a multi-year period (2002–2006). Significant accumulation in the leaves was evident for As and V, but not so regularly for Cd. Slightly decreasing temporal trends of V and As ac-cumulated in the leaf tissues were observed over the years. During the time span, the concentrations of Cd remained approximately on the same level, except in May 2002 and September 2005, when a rapid increase was observed. The May–September accumulations of As and V were higher in horse chestnut than in linden, although both may be used as biomonitors for these elements, and optionally for Cd in conditions of its high atmospheric loadings

    Phylogenetic analysis of porcine circovirus 3 circulating in Canadian pigs

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    Introduction: Porcine circovirus 3 (PCV3) has been detected in pigs worldwide and associated with several clinical signs. Methods: To investigate the genetic diversity of PCV3 strains circulating in Canada, 44 PCV3 positive samples from Saskatchewan (2/44), Manitoba (2/44), Quebec (4/44), Alberta (11/44) and Ontario (25/44) submitted to diagnostic laboratories in Canada between 2019 and 2021 were sequenced and analyzed. Results: Phylogenetic analysis of capsid genes showed that all of the 44 Canadian strains classified into PCV3a and segregated into seven lineages with common amino acid changes observed at A24V, R27K, N56D, T77S, Q98R, L150I (F) and R168K positions. Conclusion: Future studies are required to determine whether the polymorphisms in capsid proteins, as revealed in this study, could be associated with differences in the pathogenicity or antigenicity of PCV3 strains. This is the first phylogenetic analysis of PCV3 strains among different provinces in Canada
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