37,167 research outputs found
Analysis of lunar and solar effects on the motion of close earth satellites
Lunar and solar effects on motion of close earth satellite
CaII and NaI absorption signatures from the circumgalactic gas of the Milky Way
We combine CaII/NaI absorption and HI 21 cm emission line measurements to
analyse the metal abundances, the distribution, the small-scale structure, and
the physical conditions of intermediate- and high-velocity gas in the Galactic
halo.Comment: 2 pages, 1 figure, to appear in proceeding of "Galaxies in the Local
Volume" Sydney 8-13 July 200
The Molonglo Galactic Plane Survey (MGPS-2): Compact Source Catalogue
We present the first data release from the second epoch Molonglo Galactic
Plane Survey (MGPS-2). MGPS-2 was carried out with the Molonglo Observatory
Synthesis Telescope at a frequency of 843 MHz and with a restoring beam of 45
arcsec x 45 arcsec cosec(dec), making it the highest resolution large scale
radio survey of the southern Galactic plane. It covers the range |b| < 10 deg
and 245 deg < l < 365 deg and is the Galactic counterpart to the Sydney
University Molonglo Sky Survey (SUMSS) which covers the whole southern sky with
dec 10 deg).
In this paper we present the MGPS-2 compact source catalogue. The catalogue
has 48,850 sources above a limiting peak brightness of 10 mJy/beam. Positions
in the catalogue are accurate to 1 arcsec - 2 arcsec. A full catalogue
including extended sources is in preparation. We have carried out an analysis
of the compact source density across the Galactic plane and find that the
source density is not statistically higher than the density expected from the
extragalactic source density alone.
We also present version 2.0 of the SUMSS image data and catalogue which are
now available online. The data consists of 629 4.3 deg x 4.3 deg mosaic images
covering the 8100 deg^2 of sky with dec 10 deg. The
catalogue contains 210,412 radio sources to a limiting peak brightness of 6
mJy/beam at dec -50 deg. We describe the
updates and improvements made to the SUMSS cataloguing process.Comment: 12 pages, 9 figures, to be published in MNRAS Note that Figures 8 and
9 are much lower resolution than in the published versio
Modelling the response of vascular tumours to chemotherapy: A multiscale approach
An existing multiscale model is extended to study the response of a vascularised tumour to treatment with chemotherapeutic drugs which target proliferating cells. The underlying hybrid cellular automaton model couples tissue-level processes (e.g. blood flow, vascular adaptation, oxygen and drug transport) with cellular and subcellular phenomena (e.g. competition for space, progress through the cell cycle, natural cell death and drug-induced cell kill and the expression of angiogenic factors). New simulations suggest that, in the absence of therapy, vascular adaptation induced by angiogenic factors can stimulate spatio-temporal oscillations in the tumour's composition.\ud
\ud
Numerical simulations are presented and show that, depending on the choice of model parameters, when a drug which kills proliferating cells is continuously infused through the vasculature, three cases may arise: the tumour is eliminated by the drug; the tumour continues to expand into the normal tissue; or, the tumour undergoes spatio-temporal oscillations, with regions of high vascular and tumour cell density alternating with regions of low vascular and tumour cell density. The implications of these results and possible directions for future research are also discussed
Detection of broad 21-cm absorption at z = 0.656 in the complex sight-line towards 3C336
We report the detection of 21-cm absorption at z = 0.656 towards 1622+238
(3C336). The line is very broad with a Full-Width Half Maximum (FWHM) of 235
km/s, giving a velocity integrated optical depth of 2.2 km/s. The centroid of
the line is offset from that of the known damped Lyman-alpha absorption (DLA)
system by 50 km/s, and if the Lyman-alpha and 21-cm absorption are due to the
same gas, we derive a spin temperature of < 60 K, which would be the lowest yet
in a DLA. The wide profile, which is over four times wider than that of any
other DLA, supports the hypothesis that the hydrogen absorption is occurring
either in the disk of a large underluminous spiral or a group of dim
unidentified galaxies, associated with the single object which has been
optically identified at this redshift.Comment: 5 pages, 3 figures, accepted by MNRAS Letter
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