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&

Revisiting Joan Acker's work with the support of Joan Acker

This article is a personal tribute to working with Joan Acker. I worked with Joan in 2012, helping to edit her own thoughts and reflection on how other academics evaluate and used her own theorizing, specifically her seminal work on the gender substructure and inequality regimes. However, while this article is a tribute to Joan, her work and her thinking; it is also a personal thank you to someone I will miss for her generosity and also her activism in challenging inequalities in organizations and beyond. She continues to inspire me and hopefully others to challenge for social justice. In her 80s, Joan remained committed to addressing inequalities in social relations and how these were experienced within a dynamic social and work environment. During our collaboration, she called upon academics to put theory into practice to help address visible and invisible inequalities in organizational processes. This article is inspired by that experience and it will reveal Joan's views about her own, and other academics, theorizing of her two key concepts: the gender substructure of organizations and inequality regimes in organizations and the overlap with intersectionality. This article will offer a unique opportunity to gain insight into Joan's thinking as an academic sociologist as well as a feminist activist thereby uniting Joan as a person with her concepts

Aerodynamic and acoustic effects of eliminating core swirl from a full scale 1.6 stage pressure ratio fan (QF-5A)

Fan QF-5A was a modification of fan QF-5 which had an additional core stator and adjusted support struts to turn the core exit flow from a 30 deg swirl to the axial direction. This modification was necessary to eliminate the impingement of the swirling core flow on the axial support pylon of the NASA-Lewis Quiet Fan Facility that caused aerodynamic, acoustic and structural problems with the original fan stage at fan speeds greater than 85 percent of design. The redesigned fan QF-5A did obtain the design bypass ratio with an increased core airflow suggesting that the flow problem was resolved. Acoustically, the redesigned stage showed a low frequency broadband noise reduction compared to the results for fan QF-5 at similar operating conditions

ADEPT - Next Generation Process Management Technology

In the ADEPT project we have been working on the design and implementation of a next generation process management technology for several years. Based on a conceptual framework for dynamic process changes, on innovative process support functions, and on advanced implementation concepts, the developed system enables the realization of adaptive, process-aware information systems (PAIS). Basically, process changes can take place at the process type as well as the process instance level: Changes of single process instances may have to be carried out in an ad-hoc manner (e.g., to deal with an exceptional situation) and must not affect system robustness and consistency. Process type changes, in turn, must be quickly accomplished in order to adapt the PAIS to business process changes. This may also include the migration of (thousands of) instances to the new process schema (if desired). Important requirements are to perform respective migrations on-the-fly, to preserve correctness, and to avoid performance penalties

Testing neutrino instability with active galactic nuclei

Active galactic nuclei and gamma ray bursts at cosmological distances are sources of high-energy electron and muon neutrinos and provide a unique test bench for neutrino instability. The typical lifetime-to-mass ratio one can reach there is $\tau/m\sim 500 Mpc/cE_{\nu}\sim 500$ s/eV. We study the rapid decay channel $\nu_i\to\nu_j+\phi$, where $\phi$ is a massless or very light scalar (possibly a Goldstone boson), and point out that one can test the coupling strength of $g_{ij}\nu_i\nu_j$ down to g_{ij}\lsim 10^{-8} eV/m by measuring the relative fluxes of $\nu_{e}$, $\nu_{\mu}$ and $\nu_{\tau}$. This is orders of magnitude more stringent bound than what one can obtain in other phenomena, e.g. in neutrinoless double beta decay with scalar emission.Comment: 3 page

ADEPT2 - Next Generation Process Management Technology

If current process management systems shall be applied to a broad spectrum of applications, they will have to be significantly improved with respect to their technological capabilities. In particular, in dynamic environments it must be possible to quickly implement and deploy new processes, to enable ad-hoc modifications of single process instances at runtime (e.g., to add, delete or shift process steps), and to support process schema evolution with instance migration, i.e., to propagate process schema changes to already running instances. These requirements must be met without affecting process consistency and by preserving the robustness of the process management system. In this paper we describe how these challenges have been addressed and solved in the ADEPT2 Process Management System. Our overall vision is to provide a next generation process management technology which can be used in a variety of application domains

MSW mediated neutrino decay and the solar neutrino problem

We investigate the solar neutrino problem assuming simultaneous presence of MSW transitions in the sun and neutrino decay on the way from sun to earth. We do a global $\chi^2$-analysis of the data on total rates in Cl, Ga and Superkamiokande (SK) experiments and the SK day-night spectrum data and determine the changes in the allowed region in the \dm - \tan^2\theta plane in presence of decay. We also discuss the implications for unstable neutrinos in the SNO experiment.Comment: Final version to appear in Phys. Rev.

A long trail behind the planetary nebula HFG1 (PK 136+05) and its precataclysmic binary central star V664 Cas

A deep wide-field image in the light of the Halpha+[N II] emission lines, of the planetary nebula HFG1 which surrounds the precataclysmic binary system V664 Cas, has revealed a tail of emission at least 20' long, at a position angle of 316deg. Evidence is presented which suggests that this is an ~10^5 y old trail of shocked material, left behind V664 Cas as it ejects matter whilst ploughing through its local interstellar media at anywhere between 29 and 59 km/s depending on its distance from the Sun.Comment: 3 pages, 1 figure, accepted for publication in MNRA

Spectral analysis of the background in ground-based, long-slit spectroscopy

This paper examines the variations, because of atmospheric extinction, of broad-band visible spectra, obtained from long-slit spectroscopy, in the vicinity of some stars, nebulae, and one faint galaxy.Comment: 12 figure