13,665 research outputs found
Reading the Lack of the Body: The Writing of the Marquis de Sade
At the opening of her article, Acker writes, "I am using this essay to do two things. To read a short passage from Philosophy in the Bedroom by the Marquis de Sade. To read one of his tales. The more that I write my own novels, the more it seems to me that to write is to read." The two main divisions in the text bear the following headings: "To write in order to lead the reader into a labyrinth from which the reader cannot emerge without destroying the world" and "Reading a tale by de Sade: writing or reading whose only purpose is to destroy itself.
Chemical compositions and plasma parameters of planetary nebulae with Wolf-Rayet and wels type central stars
Aims: Chemical compositions and other properties of planetary nebulae around
central stars of spectral types [WC], [WO], and wels are compared with those of
`normal' central stars, in order to clarify the evolutionary status of each
type and their interrelation. Methods: We use plasma diagnostics to derive from
optical spectra the plasma parameters and chemical compositions of 48 planetary
nebulae. We also reanalyze the published spectra of a sample of 167 non-WR PN.
The results as well as the observational data are compared in detail with those
from other studies of the objects in common. Results: The central star's
spectral type is clearly correlated with electron density, temperature and
excitation class of the nebula, [WC] nebulae tend to be smaller than the other
types. All this corroborates the view of an evolutionary sequence from cool [WC
11] central stars inside dense, low excitation nebulae towards hot [WO 1] stars
with low density, high excitation nebulae. The wels PN, however, appear to be a
separate class of objects, not linked to WRPN by evolution, --abridged--Comment: 17 pages, 28 figures, Accepted in A&A. Accepted in A&
The Analogous Spaces of Paul Otlet (1868-1944)
info:eu-repo/semantics/nonPublishe
Is neutrino decay really ruled out as a solution to the atmospheric neutrino problem from Super-Kamiokande data?
In this paper we do a detailed -analysis of the 848 days of
Super-Kamiokande(SK) atmospheric neutrino data under the assumptions of
oscillation and neutrino decay. For the latter we take the
most general case of neutrinos with non-zero mixing and consider the
possibilities of the unstable component in decaying to a state with
which it mixes (scenario (a)) and to a sterile state with which it does not mix
(scenario (b)). In the first case (mass squared difference between
the two mass states which mix) has to be 0.1 from constraints on
decays while for the second case can be unconstrained. For case
(a) does not enter the -analysis while in case (b) it
enters the -analysis as an independent parameter. In scenario (a) there
is \dm averaged oscillation in addition to decay and this gets ruled out at
100.0% C.L. by the latest SK data. Scenario (b) on the other hand gives a
reasonably good fit to the data for \dm .Comment: Version to appear in Astropart. Phy
Proposed nomenclature for Extragalactic Planetary Nebulae
The ability to identify and distinguish between the wide variety of celestial
objects benefits from application of a systematic and logical nomenclature.
This often includes value-added information within the naming convention which
can aid in placing the object positionally either via an RA/DEC or l,b
concatenation. All new nomenclatures should be created following IAU
guidelines. However as the number density of specific object types on the sky
increases, as in the case of PN in external galaxies, a useful positional
identifier becomes problematic. This brief but timely paper attempts to
progress the debate on this vexing issue for the case of extragalactic
planetary nebulae (EPN). There is a clear need to rationalise the current
ad-hoc system now that many thousands of Extragalactic PN are being discovered.Comment: 3 pages, no figures, LaTeX, to be published in Proceedings of the ESO
workshop on Planetary Nebulae beyond the Milky Way held at ESO, Garching, May
19-21, 200
Newly discovered halos and outer features around southern planetary nebulae
We have used the SuperCOSMOS H-alpha Survey to look for faint outer
structures such as halos, ansae and jets around known planetary nebulae across
4000 square degrees of the southern Milky Way. Our search will contribute to a
more accurate census of these features in the Galactic PN population. Candidate
common-envelope PNe have also been identified on the basis of their
microstructures. We also intend to determine more reliable distances for these
PNe, which should allow a much better statistical basis for the post-AGB total
mass budget. Our survey offers fresh scope to address this important issue.Comment: 2 pages, 1 figure. To be published in Planetary Nebulae: an Eye to
the Future, Proceedings of IAU Symposium 283, held in Puerto de la Cruz,
Tenerife, Spain, July 25-29 201
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