Distribution and kinematics of atomic and molecular gas inside the Solar circle

The detailed distribution and kinematics of the atomic and the CO-bright molecular hydrogen in the disc of the Milky Way inside the Solar circle are derived under the assumptions of axisymmetry and pure circular motions. We divide the Galactic disc into a series of rings, and assume that the gas in each ring is described by four parameters: its rotation velocity, velocity dispersion, midplane density and its scale height. We fit these parameters to the Galactic HI and CO (J=1-0) data by producing artificial HI and CO line-profiles and comparing them with the observations. Our approach allows us to fit all parameters to the data simultaneously without assuming a-priori a radial profile for one of the parameters. We present the distribution and kinematics of the HI and H2 in both the approaching (QIV) and the receding (QI) regions of the Galaxy. Our best-fit models reproduces remarkably well the observed HI and CO longitude-velocity diagrams up to a few degrees of distance from the midplane. With the exception of the innermost 2.5 kpc, QI and QIV show very similar kinematics. The rotation curves traced by the HI and H2 follow closely each other, flattening beyond R=6.5 kpc. Both the HI and the H2 surface densities show a) a deep depression at 0.5<R<2.5 kpc, analogous to that shown by some nearby barred galaxies, b) local overdensities that can be interpreted in terms of spiral arms or ring-like features in the disk. The HI (H2) properties are fairly constant in the region outside the depression, with typical velocity dispersion of 8.9+/-1.1 (4.4+/-1.2) km/s, density of 0.43+/-0.11 (0.42+/-0.22) cm-3 and HWHM scale height of 202+/-28 (64+/-12) pc. We also show that the HI opacity in the LAB data can be accounted for by using an `effective' spin temperature of about 150 K: assuming an optically thin regime leads to underestimate the HI mass by about 30%.Comment: 23 pages, 24 figures. Accepted by A&

Direct Visualization of Formylpeptide Receptor Binding on Rounded and Polarized Human Neutrophils: Cellular and Receptor Heterogeneity

We have used light microscope autoradiography to visualize binding of the formylhexa‐peptide, N‐formyl‐norleucyl‐leucyl‐phenylalanyl‐norleucyl‐(125l)tyrosyl‐lysine to rounded and spontaneously polarized human polymorphonuclear leukocytes. These cells possess receptors known to bind with high specificity and great avidity to the chemotactic formylpeptides. Cells adherent to glass slides were exposed to (125I)‐hexapeptide at 4°, fixed, and autoradiographed. Hexapeptide binding was studied over the biologically active range of peptide concentrations varying from 0.63 nM to 10 nM and autoradiographic silver grains counted on 200 rounded or 50 polarized cells at each concentration. Examination of histograms plotted from these data revealed for rounded cells: 1) two major peaks at each concentration indicating the existence of two neutrophil subpopulations, the predominant subpopulation binding one‐half as much formylpeptide (peak I) as the other (peak II); 2) progressively increasing proportions of cells in peak II as the free hexapeptide concentration increased. Accordingly, at 0.63 nM hexapeptide, peak II comprised only 8% of the total cell number, whereas at 10 nM, this peak represented 35% of the total cells. This suggested that different types of receptors may exist in the two cell subpopulations (high/low affinity or high/low negative cooperativity) and that these receptor types were expressed differentially on these subpopulations. Thus, cellular heterogeneity within the neutrophil population and receptor heterogeneity among hexapeptide receptors on an individual cell were both observed here. Each of these may significantly affect neutrophil functional responses to the chemotactic formylpeptides and may explain, at least in part, the curvilinearity in the Scatchard plots of formylpeptide receptor binding that has recently been reported.At higher concentrations of peptide (5 nM), spontaneously polarized PMN bound hexapeptide more or less uniformly over the entire cell surface. However, at lower concentrations, hexapeptide binding was markedly shifted toward the cell anterior. As a group, polarized PMN bound similar total quantities of hexapeptide, as did rounded PMN at each peptide concentration tested. Receptors displaying high‐ and low‐affinity characteristics were, however, distributed asymmetrically over the cell surface, with the high‐affinity type receptors predominantly on the anterior one‐half of the cell. Such an asymmetric distribution may serve to initiate or perpetuate cell locomotion.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141552/1/jlb0377.pd

Contemporary outcomes of continuous-flow biventricular assist devices.

BACKGROUND: Significant right ventricular failure (RVF) complicating left ventricular assist device (LVAD) placement has been reported at 10–30%. Although primarily indicated for left ventricular failure, ventricular assist devices (VADs) have become utilized in a biventricular setup to combat right ventricular failure (RVF) following LVAD implantation. With the advent of continuous-flow LVADs (CF-LVADs) superseding their pulsatile predecessors, the shift towards CF-biventricular assist devices (CF-BiVADs) come with the prospect of improved outcomes over previous pulsatile BiVADs. We aim to review the literature and determine the outcomes of CF-BiVAD recipients. METHODS: A systematic review was performed to determine the outcomes of CF-BiVADs. Pre-operative demographics and device configuration data was collected. Primary outcomes evaluated were short-term survival, long-term survival, duration of support, and survival to transplant. Secondary outcomes evaluated included intensive care unit (ICU) and hospital length of stay (ICU-LOS and HLOS, respectively), pump thrombosis, pump exchange. Median and interquartile range was reported where appropriate. A major limitation was the likely overlap of cohorts across publications, which may have contributed to some selection bias. RESULTS: Of 1,282 screened, 12 publications were evaluated. Sample size ranged from 4 to 93 CF-BiVAD recipients, and follow-up ranged from 6 to 24 months. Mean age ranged from 34 to 52 years old. Forty-five percent of CF-BiVADs had right atrial (RA-) inflow cannulation, with the remaining being right ventricular (RV). Thirty-day survival was a median of 90% (IQR 82–97.8%) and 12-month survival was a median of 58.5% (IQR 47.5–62%). Where reported, rate of pump thrombosis (predominantly the right VAD) was a median of 31% (IQR 14–36%), although pump exchange was only 9% (IQR 1.5–12.5%). CONCLUSIONS: RVF post-LVAD implantation is a high morbidity and mortality complication. There is no on-label continuous-flow RVAD currently available. Thus, the modifications of LVADs for right ventricular support to combat pump thrombosis has resulted in various techniques. BiVAD recipients are predominantly transplant candidates, and complications of pump thrombosis and driveline infection whilst on wait-list are of great consequence. This study demonstrates the need for an on-label CF-BiVAD

Successful application of PSF-R techniques to the case of the globular cluster NGC 6121 (M 4)

Context. Precise photometric and astrometric measurements on astronomical images require an accurate knowledge of the point spread function (PSF). When the PSF cannot be modelled directly from the image, PSF-reconstruction techniques become the only viable solution. So far, however, their performance on real observations has rarely been quantified. Aims. In this Letter, we test the performance of a novel hybrid technique, called PRIME, on Adaptive Optics-assisted SPHERE/ZIMPOL observations of the Galactic globular cluster NGC 6121. Methods. PRIME couples PSF-reconstruction techniques, based on control-loop data and direct image fitting performed on the only bright point-like source available in the field of view of the ZIMPOL exposures, with the aim of building the PSF model. Results. By exploiting this model, the magnitudes and positions of the stars in the field can be measured with an unprecedented precision, which surpasses that obtained by more standard methods by at least a factor of four for on-axis stars and by up to a factor of two on fainter, off-axis stars. Conclusions. Our results demonstrate the power of PRIME in recovering precise magnitudes and positions when the information directly coming from astronomical images is limited to only a few point-like sources and, thus, paving the way for a proper analysis of future Extremely Large Telescope observations of sparse stellar fields or individual extragalactic objects

A brief introduction to nomography: graphical representation of mathematical relationships

© 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group. Nomographs (or nomograms, or alignment charts) are graphical representations of mathematical relationships (extending to empirical relationships of data) which are used by simply applying a straightedge across the plot through points on scales representing independent variables, which then crosses the corresponding datum point for the dependent variable; the choice among independent and dependent variable is arbitrary so that each variable may be determined in terms of the others. Examples of nomographs in common current use compute the lift available for a hot-air balloon, the boiling points of solvents under reduced pressure in the chemistry laboratory, and the relative forces in a centrifuge in a biochemical laboratory. Sundials represent another ancient yet widely familiar example. With the advent and ready accessibility of the computer, printed mathematical tables, slide rules and nomographs became generally redundant. However, nomographs provide insight into mathematical relationships, are useful for rapid and repeated application, even in the absence of calculational facilities, and can reliably be used in the field. Many nomographs for various purposes may be found online. This paper describes the origins and development of nomographs, illustrating their use with some relevant examples. A supplementary interactive Excel file demonstrates their application for some simple mathematical operations