1,369 research outputs found
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&
Determining firms׳ utility functions and competitive roles from data on market shares using Lotka–Volterra models
AbstractIn this article, we include data on historical and estimated market shares of two markets. In particular, we include annual data on the market shares of the Japanese beer market (1963–2000) and biannual data on the market shares of the mobile phones market in Greece (1998–2007). In addition, we estimate monthly data on market shares for both markets. We show how this data can be used to derive firms’ utility functions and their competitive roles
Determining firms' utility functions and competitive roles from data on market shares using Lotka-Volterra models
In this article, we include data on historical and estimated market shares of two markets. In particular, we include annual data on the market shares of the Japanese beer market (1963-2000) and biannual data on the market shares of the mobile phones market in Greece (1998-2007). In addition, we estimate monthly data on market shares for both markets. We show how this data can be used to derive firms' utility functions and their competitive roles
Many Identities, One Nation: The Revolution and Its Legacy in the Mid-Atlantic
Many Identities, One Nation
The Revolution and Its Legacy in the Mid-Atlantic
Liam Riordan
Philadelphia, University of Pennsylvania Press, 2007
392 pages, 6 1/8 x 9 1/4 , 27 illus.
Cloth ISBN 978-0-8122-4001-6
A volume in the Early American Studies serie
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
Designing Collaborative and Mediated Experiences with Networked Circuit-Bent Devices
Circuit bending provides creative methods of generating sound by subverting a device’s normal operation through hacking. While the means of interacting with hacked devices in performance are primarily limited to tactile controls and explicitly mapped actions, exploring alternative methods of engaging with these instruments would allow for mediation systems and collaborative performance design to enhance the use of nostalgic devices in audio/visual art. This paper discusses the artistic benefits of blending the musical and aesthetic practices of circuit bending with the field of networked musical performance. We present the artistic benefits of traditional circuit bending and methods of extending networked performance techniques to the practice. This is followed by a discussion of Bendit_I/O—a framework for designing cyber-hacked readymades—opening the door to innovative design practices for using hacked hardware in collaborative environments. We also discuss Pepper\u27s Ghost, a multimedia installation created with networked circuit-bent devices with the goal of exploring these concepts
The origin of the high-velocity cloud complex C
High-velocity clouds consist of cold gas that appears to be raining down from
the halo to the disc of the Milky Way. Over the past fifty years, two competing
scenarios have attributed their origin either to gas accretion from outside the
Galaxy or to circulation of gas from the Galactic disc powered by supernova
feedback (galactic fountain). Here we show that both mechanisms are
simultaneously at work. We use a new galactic fountain model combined with
high-resolution hydrodynamical simulations. We focus on the prototypical cloud
complex C and show that it was produced by an explosion that occurred in the
Cygnus-Outer spiral arm about 150 million years ago. The ejected material has
triggered the condensation of a large portion of the circumgalactic medium and
caused its subsequent accretion onto the disc. This fountain-driven cooling of
the lower Galactic corona provides the low-metallicity gas required by chemical
evolution models of the Milky Way's disc.Comment: 6 pages, 4 figures, 1 table; accepted by MNRA
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