2,321 research outputs found
Polyunsaturated fatty acid-derived lipid mediators and T cell function
Copyright © 2014 Nicolaou, Mauro, Urquhart and Marelli-Berg . This is an open-
access article distributed under the terms of the
Creative Commons Attribution License
(CC BY)
. The use, distribution or reproduction in other forums is permitted, provided
the original author(s) or licensor are credited and that the original publication in this
journal is cited, in accordance with accepted academic practice. No use, distribution or
reproduction is permitted which does not comply with these terms
Polyunsaturated fatty acid-derived lipid mediators and T cell function
Copyright © 2014 Nicolaou, Mauro, Urquhart and Marelli-Berg . This is an open-
access article distributed under the terms of the
Creative Commons Attribution License
(CC BY)
. The use, distribution or reproduction in other forums is permitted, provided
the original author(s) or licensor are credited and that the original publication in this
journal is cited, in accordance with accepted academic practice. No use, distribution or
reproduction is permitted which does not comply with these terms
Solubility behaviour, crystallisation kinetics and pour point : a comparison of linear alkane and triacyl glyceride solute/solvent mixtures
Mixtures of either a hydrocarbon wax in a hydrocarbon solvent or a long chain triacyl glyceride (TAG) in a TAG solvent show complex solubility boundary temperature hysteresis and precipitated crystal network formation leading to gelation. For these industrially-important systems, we show how the equilibrium solubility and its hysteresis, crystallisation kinetics and pour point temperature vary with solute concentration for representative examples of both hydrocarbon (n-tetracosane (C24) solute in n-heptane (C7) solvent) and TAG (tristearin (SSS) solute in tricaprylin (CCC) solvent) mixtures. The behaviour is modelled with good accuracy; thereby providing a useful aid to formulation and process optimisation
The implementation and use of Ada on distributed systems with reliability requirements
The issues involved in the use of the programming language Ada on distributed systems are discussed. The effects of Ada programs on hardware failures such as loss of a processor are emphasized. It is shown that many Ada language elements are not well suited to this environment. Processor failure can easily lead to difficulties on those processors which remain. As an example, the calling task in a rendezvous may be suspended forever if the processor executing the serving task fails. A mechanism for detecting failure is proposed and changes to the Ada run time support system are suggested which avoid most of the difficulties. Ada program structures are defined which allow programs to reconfigure and continue to provide service following processor failure
The RMS Survey: 6 cm continuum VLA observations towards candidate massive YSOs in the northern hemisphere
(Abridged) Context: The Red MSX Source (RMS) survey is an ongoing
multi-wavelength observational programme designed to return a large,
well-selected sample of massive young stellar objects (MYSOs). We have
identified 2000 MYSO candidates located throughout the Galaxy by
comparing the colours of MSX and 2MASS point sources to those of known MYSOs.
Aims: To identify the populations of UCHII regions and PNe within the sample
and examine their Galactic distribution. Method: We have conducted high
resolution radio continuum observations at 6 cm towards 659 MYSO candidates in
the northern hemisphere (10\degr< l < 250\degr) using the VLA. In addition to
these targeted observations we present archival data towards a further 315 RMS
sources extracted from a previous VLA survey of the inner Galaxy. Results: We
find radio emission towards 272 (27% of the observed sample). Using
results from other parts of our multi-wavelength survey we separate these
RMS-radio associations into two distinct types of objects, classifying 51 as
PNe and a further 208 as either compact or UC HII regions. Using this well
selected sample of HII regions we estimate their Galactic scale height to be
0.6\degr. Conclusions: Using radio continuum and archival data we have
identified 79 PNe and 391 HII regions within the northern RMS catalogue. We
estimate the total fraction of contamination by PNe in the RMS sample is of
order 10%. The sample of HII regions is probably the best representation to
date of the Galactic population of HII regions as a whole.Comment: Accepted for publication in Astronomy and Astrophysics. 15 pages, 9
figures and 5 tables. Full versions of Tables 3, 4 and 5 and Figs. 2, 4 and 7
will only be available via CDS or the RMS website at
http:/www.ast.leeds.ac.uk/cgi-bin/RMS/RMS_VLA_IMAGES.cg
The implementation and use of Ada on distributed systems with high reliability requirements
The use and implementation of Ada in distributed environments in which reliability is the primary concern were investigated. In particular, the concept that a distributed system may be programmed entirely in Ada so that the individual tasks of the system are unconcerned with which processors they are executing on, and that failures may occur in the software or underlying hardware was examined. Progress is discussed for the following areas: continued development and testing of the fault-tolerant Ada testbed; development of suggested changes to Ada so that it might more easily cope with the failure of interest; and design of new approaches to fault-tolerant software in real-time systems, and integration of these ideas into Ada
New ammonia masers towards NGC6334I
We report the detection of new ammonia masers in the non-metastable (8,6) and
(11,9) transitions towards the massive star forming region NGC6334I.
Observations were made with the ATCA interferometer and the emitting region
appears unresolved in the 2.7" x 0.8" beam, with deconvolved sizes less than an
arcsecond. We estimate peak brightness temperatures of 7.8 x 10^5 and 1.2 x
10^5 K for the (8,6) and (11,9) transitions, respectively. The masers appear
coincident both spatially and in velocity with a previously detected ammonia
(6,6) maser. We also suggest that emission in the (10,9), (9,9) and (7,6)
transitions may also be masers, based on their narrow line widths and
overlapping velocity ranges with the above masers, as observed with the
single-dish Mopra radiotelescope
Characterisation of the Mopra Radio Telescope at 16--50 GHz
We present the results of a programme of scanning and mapping observations of
astronomical masers and Jupiter designed to characterise the performance of the
Mopra Radio Telescope at frequencies between 16-50 GHz using the 12-mm and 7-mm
receivers. We use these observations to determine the telescope beam size, beam
shape and overall telescope beam efficiency as a function of frequency. We find
that the beam size is well fit by / over the frequency range with a
correlation coefficient of ~90%. We determine the telescope main beam
efficiencies are between ~48-64% for the 12-mm receiver and reasonably flat at
~50% for the 7-mm receiver. Beam maps of strong HO (22 GHz) and SiO masers
(43 GHz) provide a means to examine the radial beam pattern of the telescope.
At both frequencies the radial beam pattern reveals the presence of three
components, a central `core', which is well fit by a Gaussian and constitutes
the telescopes main beam, and inner and outer error beams. At both frequencies
the inner and outer error beams extend out to approximately 2 and 3.4 times the
full-width half maximum of the main beam respectively. Sources with angular
sizes a factor of two or more larger than the telescope main beam will couple
to the main and error beams, and therefore the power contributed by the error
beams needs to be considered. From measurements of the radial beam power
pattern we estimate the amount of power contained in the inner and outer error
beams is of order one-fifth at 22 GHz rising slightly to one-third at 43 GHz.Comment: Accepted for publication in PAS
ATLASGAL - environments of 6.7 GHz methanol masers
Using the 870 micron APEX Telescope large area survey of the Galaxy, we have identified 577 submillimetre continuum sources with masers from the methanol multibeam survey in the region 280deg lt ell lt 20deg; |b| lt 1deg.5 94 per cent of methanol masers in the region are associated with submillimetre dust emission. We estimate masses for tilde450 maser-associated sources and find that methanol masers are preferentially associated with massive clumps. These clumps are centrally condensed, with envelope structures that appear to be scale-free, the mean maser position being offset from the peak column density by 0 plusmn 4 arcsec. Assuming a Kroupa initial mass function and a star formation efficiency of tilde30 per cent, we find that over two-thirds of the clumps are likely to form clusters with masses gt20 M. Furthermore, almost all clumps satisfy the empirical mass-size criterion for massive star formation. Bolometric luminosities taken from the literature for tilde100 clumps range between tilde100 and 10 L. This confirms the link between methanol masers and massive young stars for 90 per cent of our sample. The Galactic distribution of sources suggests that the star formation efficiency is significantly reduced in the Galactic Centre region, compared to the rest of the survey area, where it is broadly constant, and shows a significant drop in the massive star formation rate density in the outer Galaxy. We find no enhancement in source counts towards the southern Scutum-Centaurus arm tangent at ell tilde 315deg, which suggests that this arm is not actively forming stars.Peer reviewe
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