7,458 research outputs found
Planning for Planning - Coal: Issues for the Eighties
This collaborative paper is based on a meeting held at IIASA in November 1980. The meeting was part of a sequence of discussions arranged by IIASA in conjunction with the Polish Academy of Sciences and the Polish Mining Industry. A previous meeting had been held at Szczyrk, Poland in November 1979, and the proceedings are available as IIASA Working/Collaborative Papers, WP-80-140, CP-80-23, and CP-80-24. These coal industry meetings were part of a research program at IIASA under the generic title "Issues for the Eighties" in which systems analysts and managers from a given industry met to exchange ideas and information, as well as to explore and develop a strategy of using systems analysis, rather than using it merely as a tool to be brought in for certain well-defined problems.
The subject "Planning for Planning" was used as a shorthand to explore the use of systems analysis in the planning of new capacity for deep mining in hard coal. The discussions were attended by 17 representatives for 7 countries, and 13 papers were presented or tabled at the meeting. These are reproduced separately as IIASA Collaborative Paper CP-82-80.
This paper, which summarizes the discussion, structures the planning process and discusses the place of systems analysis within it. It also presents a state-of-the-art account of the uses of systems analysis for major investment planning in the coal industry, and indicates areas for future research. The summaries have been prepared in conjunction with Bill Hancock and Mike Sadnicki of the Operational Research Executive, National Coal Board, UK
Polarization of macrophages toward M2 phenotype is favored by reduction in iPLA2β (group VIA phospholipase A2)*
Macrophages are important in innate and adaptive immunity. Macrophage participation in inflammation or tissue repair is directed by various extracellular signals and mediated by multiple intracellular pathways. Activation of group VIA phospholipase A2 (iPLA2β) causes accumulation of arachidonic acid, lysophospholipids, and eicosanoids that can promote inflammation and pathologic states. We examined the role of iPLA2β in peritoneal macrophage immune function by comparing wild type (WT) and iPLA2β−/− mouse macrophages. Compared with WT, iPLA2β−/− macrophages exhibited reduced proinflammatory M1 markers when classically activated. In contrast, anti-inflammatory M2 markers were elevated under naïve conditions and induced to higher levels by alternative activation in iPLA2β−/− macrophages compared with WT. Induction of eicosanoid (12-lipoxygenase (12-LO) and cyclooxygenase 2 (COX2))- and reactive oxygen species (NADPH oxidase 4 (NOX4))-generating enzymes by classical activation pathways was also blunted in iPLA2β−/− macrophages compared with WT. The effects of inhibitors of iPLA2β, COX2, or 12-LO to reduce M1 polarization were greater than those to enhance M2 polarization. Certain lipids (lysophosphatidylcholine, lysophosphatidic acid, and prostaglandin E2) recapitulated M1 phenotype in iPLA2β−/− macrophages, but none tested promoted M2 phenotype. These findings suggest that (a) lipids generated by iPLA2β and subsequently oxidized by cyclooxygenase and 12-LO favor macrophage inflammatory M1 polarization, and (b) the absence of iPLA2β promotes macrophage M2 polarization. Reducing macrophage iPLA2β activity and thereby attenuating macrophage M1 polarization might cause a shift from an inflammatory to a recovery/repair milieu
Optical Properties of High-Frequency Radio Sources from the Australia Telescope 20 GHz (AT20G) Survey
Our current understanding of radio-loud AGN comes predominantly from studies
at frequencies of 5 GHz and below. With the recent completion of the Australia
Telescope 20 GHz (AT20G) survey, we can now gain insight into the
high-frequency radio properties of AGN. This paper presents supplementary
information on the AT20G sources in the form of optical counterparts and
redshifts. Optical counterparts were identified using the SuperCOSMOS database
and redshifts were found from either the 6dF Galaxy survey or the literature.
We also report 144 new redshifts. For AT20G sources outside the Galactic plane,
78.5% have optical identifications and 30.9% have redshift information. The
optical identification rate also increases with increasing flux density.
Targets which had optical spectra available were examined to obtain a spectral
classification.
There appear to be two distinct AT20G populations; the high luminosity
quasars that are generally associated with point-source optical counterparts
and exhibit strong emission lines in the optical spectrum, and the lower
luminosity radio galaxies that are generally associated with passive galaxies
in both the optical images and spectroscopic properties. It is suggested that
these different populations can be associated with different accretion modes
(cold-mode or hot-mode). We find that the cold-mode sources have a steeper
spectral index and produce more luminous radio lobes, but generally reside in
smaller host galaxies than their hot-mode counterparts. This can be attributed
to the fact that they are accreting material more efficiently. Lastly, we
compare the AT20G survey with the S-cubed semi-empirical (S3-SEX) models and
conclude that the S3-SEX models need refining to correctly model the compact
cores of AGN. The AT20G survey provides the ideal sample to do this.Comment: Accepted for publication in MNRA
A Candidate Protoplanet in the Taurus Star Forming Region
HST/NICMOS images of the class I protostar TMR-1 (IRAS04361+2547) reveal a
faint companion with 10.0" = 1400 AU projected separation. The central
protostar is itself resolved as a close binary with 0.31" = 42 AU separation,
surrounded by circumstellar reflection nebulosity. A long narrow filament seems
to connect the protobinary to the faint companion TMR-1C, suggesting a physical
association. If the sources are physically related then we hypothesize that
TMR-1C has been ejected by the protobinary. If TMR-1C has the same age and
distance as the protobinary then current models indicate its flux is consistent
with a young giant planet of several Jovian masses.Comment: 16 pages, 1 figure, Accepted by Astrophysical Journal Letters,
Related information is available at http://www.extrasolar.co
Spatiotemporal torquing of light
We demonstrate the controlled spatiotemporal transfer of transverse orbital
angular momentum (OAM) to electromagnetic waves: the spatiotemporal torquing of
light. This is a radically different situation than OAM transfer to
longitudinal, spatially-defined OAM light by stationary or slowly varying
refractive index structures such as phase plates or air turbulence. We show
that transverse OAM can be imparted to a short light pulse only for (1)
sufficiently fast transient phase perturbations overlapped with the pulse in
spacetime, or (2) energy removal from a pulse that already has transverse OAM.
Our OAM theory for spatiotemporal optical vortex (STOV) pulses [Phys. Rev.
Lett. 127, 193901 (2021)] correctly quantifies the light-matter interaction of
this experiment, and provides a torque-based explanation for the first
measurement of STOVs [Phys. Rev. X 6, 031037 (2016)]
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