440 research outputs found
Facies analysis, glauconite distribution and sequence stratigraphy of the middle Eocene Qarara Formation, El-Minya area, Egypt
AbstractThe Qarara Formation consists mainly of shale at the base and overlain by limestone at the top. The formation is Middle Eocene (Lutetian) in age. Three sections located at the eastern bank of the Nile River in El-Minya Province have been measured, described, and sampled. These sections from north to south are: Gebel Qarara, El-Sheikh Fadl, and Gebel El-Ahmar.The main microfacies identified in the studied sections are: silty claystone, silty shale, fossiliferous glauconite, glauconitic (green) sand, glauconitic fossiliferous ironstone, glauconitic bioclastic wacke-packstone, glauconitic bioclastic lime-mudstone-wackestone. These microfacies have been deposited in shallow open marine environment.Collectively the studied rocks contain two principal facies: lower argillaceous facies and upper carbonate facies that separated by glauconitic fossiliferous ironstone bed. The lower argillaceous part represents highstand systems tract (HST), whereas the upper carbonate part represents transgressive systems tract (TST). The glauconitic fossiliferous ironstone bed is recognized as a sequence boundary (SB)
Draft Genome Sequences of Strains \u3ci\u3eSalinicola socius\u3c/i\u3e SMB35\u3csup\u3eT\u3c/sup\u3e, \u3ci\u3eSalinicola\u3c/i\u3e sp. MH3R3-1 and \u3ci\u3eChromohalobacter\u3c/i\u3e sp. SMB17 From the Verkhnekamsk Potash Mining Region of Russia
Halomonads are moderately halophilic bacteria that are studied as models of prokaryotic osmoadaptation and sources of enzymes and chemicals for biotechnological applications. Despite the progress in understanding the diversity of these organisms, our ability to explain ecological, metabolic, and biochemical traits of halomonads at the genomic sequence level remains limited. This study addresses this gap by presenting draft genomes of Salinicola socius SMB35T, Salinicola sp. MH3R3–1 and Chromohalobacter sp. SMB17, which were isolated from potash mine tailings in the Verkhnekamsk salt deposit area of Russia. The analysis of these genomes confirmed the importance of ectoines and quaternary amines to the capacity of halomonads to tolerate osmotic stress and adapt to hypersaline environments. The study also revealed that Chromohalobacter and Salinicola share 75–90% of the predicted proteome, but also harbor a set of genus-specific genes, which in Salinicola amounted to approximately 0.5 Mbp. These genus-specific genome segments may contribute to the phenotypic diversity of the Halomonadaceae and the ability of these organisms to adapt to changing environmental conditions and colonize new ecological niches
WISDOM Project -- XV. Giant Molecular Clouds in the Central Region of the Barred Spiral Galaxy NGC 5806
We present high spatial resolution ( pc) Atacama Large
Millimeter/sub-millimeter Array CO(2-1) observations of the central
region of the nearby barred spiral galaxy NGC 5806. NGC 5806 has a highly
structured molecular gas distribution with a clear nucleus, a nuclear ring and
offset dust lanes. We identify spatially- and spectrally-resolved giant
molecular clouds (GMCs). These clouds have comparable sizes ()
and larger gas masses, observed linewidths () and
gas mass surface densities than those of clouds in the Milky Way disc. The size
-- linewidth relation of the clouds is one of the steepest reported so far
(), the clouds are on
average only marginally bound (with a mean virial parameter
), and high velocity dispersions
are observed in the nuclear ring. These behaviours are likely due to bar-driven
gas shocks and inflows along the offset dust lanes, and we infer an inflow
velocity of kms and a total molecular gas mass inflow rate
of M yr into the nuclear ring. The observed internal
velocity gradients of the clouds are consistent with internal turbulence. The
number of clouds in the nuclear ring decreases with azimuthal angle downstream
from the dust lanes without clear variation of cloud properties. This is likely
due to the estimated short lifetime of the clouds ( Myr), which
appears to be mainly regulated by cloud-cloud collision and/or shear processes.
Overall, it thus seems that the presence of the large-scale bar and gas inflows
to the centre of NGC 5806 affect cloud properties.Comment: Accepted for publication in MNRAS, 20 pages, 16 figure
WISDOM project -- XVI. SMBH mass in the early-type galaxies NGC0612, NGC1574, and NGC4261 from CO dynamical modelling
We present a CO dynamical estimate of the mass of the super-massive black
hole (SMBH) in three nearby early-type galaxies: NGC0612, NGC1574 and NGC4261.
Our analysis is based on Atacama Large Millimeter/submillimeter Array (ALMA)
Cycle 3-6 observations of the CO(2-1) emission line with spatial
resolutions of pc (). We detect disc-like CO
distributions on scales from pc (NGC1574 and NGC4261) to
kpc (NGC0612). In NGC0612 and NGC1574 the bulk of the gas is
regularly rotating. The data also provide evidence for the presence of a
massive dark object at the centre of NGC1574, allowing us to obtain the first
measure of its mass, M
(1 uncertainty). In NGC4261, the CO kinematics is clearly dominated by
the SMBH gravitational influence, allowing us to determine an accurate black
hole mass of M (
uncertainty). This is fully consistent with a previous CO dynamical estimate
obtained using a different modelling technique. Signs of non-circular gas
motions (likely outflow) are also identified in the inner regions of NGC4261.
In NGC0612, we are only able to obtain a (conservative) upper limit of M. This has likely to be ascribed to the
presence of a central CO hole (with a radius much larger than that of the SMBH
sphere of influence), combined with the inability of obtaining a robust
prediction for the CO velocity curve. The three SMBH mass estimates are overall
in agreement with predictions from the relation.Comment: Main text: 20 pages, 14 Figures; Appendix: 7 pages, 6 Figures.
Accepted for publication in MNRAS on 2023 March 2
Spatial and Temporal Dynamics in the Ionic Driving Force for GABAA Receptors
It is becoming increasingly apparent that the strength of GABAergic synaptic transmission is dynamic. One parameter that can establish differences in the actions of GABAergic synapses is the ionic driving force for the chloride-permeable GABAA receptor (GABAAR). Here we review some of the sophisticated ways in which this ionic driving force can vary within neuronal circuits. This driving force for GABAARs is subject to tight spatial control, with the distribution of Cl− transporter proteins and channels generating regional variation in the strength of GABAAR signalling across a single neuron. GABAAR dynamics can result from short-term changes in their driving force, which involve the temporary accumulation or depletion of intracellular Cl−. In addition, activity-dependent changes in the expression and function of Cl− regulating proteins can result in long-term shifts in the driving force for GABAARs. The multifaceted regulation of the ionic driving force for GABAARs has wide ranging implications for mature brain function, neural circuit development, and disease
Comparison of mortality hazard ratios associated with health behaviours in Canada and the United States:a population-based linked health survey study
Background Modern health surveillance and planning requires an understanding of how preventable risk factors impact population health, and how these effects vary between populations. In this study, we compare how smoking, alcohol consumption, diet and physical activity are associated with all-cause mortality in Canada and the United States using comparable individual-level, linked population health survey data and identical model specifications. Methods The Canadian Community Health Survey (CCHS) (2003–2007) and the United States National Health Interview Survey (NHIS) (2000, 2005) linked to individual-level mortality outcomes with follow up to December 31, 2011 were used. Consistent variable definitions were used to estimate country-specific mortality hazard ratios with sex-specific Cox proportional hazard models, including smoking, alcohol, diet and physical activity, sociodemographic indicators and proximal factors including disease history. Results A total of 296,407 respondents and 1,813,884 million person-years of follow-up from the CCHS and 58,232 respondents and 497,909 person-years from the NHIS were included. Absolute mortality risk among those with a ‘healthy profile’ was higher in the United States compared to Canada, especially among women. Adjusted mortality hazard ratios associated with health behaviours were generally of similar magnitude and direction but often stronger in Canada. Conclusion Even when methodological and population differences are minimal, the association of health behaviours and mortality can vary across populations. It is therefore important to be cautious of between-study variation when aggregating relative effect estimates from differing populations, and when using external effect estimates for population health research and policy development
A Study of the PDGF Signaling Pathway with PRISM
In this paper, we apply the probabilistic model checker PRISM to the analysis
of a biological system -- the Platelet-Derived Growth Factor (PDGF) signaling
pathway, demonstrating in detail how this pathway can be analyzed in PRISM. We
show that quantitative verification can yield a better understanding of the
PDGF signaling pathway.Comment: In Proceedings CompMod 2011, arXiv:1109.104
Cardiac autonomic neuropathy in patients with diabetes and no symptoms of coronary artery disease: comparison of 123I-metaiodobenzylguanidine myocardial scintigraphy and heart rate variability
PURPOSE The purpose of this study was to evaluate the prevalence of cardiac autonomic neuropathy (CAN) in a cohort of patients with type 2 diabetes, truly asymptomatic for coronary artery disease (CAD), using heart rate variability (HRV) and (123)I-metaiodobenzylguanidine ((123)I-mIBG) myocardial scintigraphy. METHODS The study group comprised 88 patients with type 2 diabetes prospectively recruited from an outpatient diabetes clinic. In all patients myocardial perfusion scintigraphy, CAN by HRV and (123)I-mIBG myocardial scintigraphy were performed. Two or more abnormal tests were defined as CAN-positive (ECG-based CAN) and one or fewer as CAN-negative. CAN assessed by (123)I-mIBG scintigraphy was defined as abnormal if the heart-to-mediastinum ratio was 25%, or the total defect score was >13. RESULTS The prevalence of CAN in patients asymptomatic for CAD with type 2 diabetes and normal myocardial perfusion assessed by HRV and (123)I-mIBG scintigraphy was respectively, 27% and 58%. Furthermore, in almost half of patients with normal HRV, (123)I-mIBG scintigraphy showed CAN. CONCLUSION The current study revealed a high prevalence of CAN in patients with type 2 diabetes. Secondly, disagreement between HRV and (123)I-mIBG scintigraphy for the assessment of CAN was observed.Cardiovascular Aspects of Radiolog
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