OP data on CD for mean opacities and radiative accelerations

All monochromatic opacity data from the Opacity Project (OP), together with all codes required for the calculation of mean opacities and radiative accelerations for any required chemical mixture, temperature and mass-density, are being put on a 700 Mb CD which will be made generally available. The present paper gives a concise summary of the contents of the CD. More complete documentation will be provided on the CD itself.Comment: 4 pages, 2 figures, submitted to MNRA

Internet sources for nursing and allied health

Lists and describes available Internet resources for nursing and allied health professionals. Procedure for subscribing and unsubscribing from the discussion lists; Newsgroups available for nurses; Accessing to gopher servers

Stratifications of inertia spaces of compact Lie group actions

We study the topology of the inertia space of a smooth $G$-manifold $M$ where $G$ is a compact Lie group. We construct an explicit Whitney stratification of the inertia space, demonstrating that the inertia space is a triangulable differentiable stratified space. In addition, we demonstrate a de Rham theorem for differential forms defined on the inertia space with respect to this stratification.Comment: 36 page

Differentiable stratified groupoids and a de Rham theorem for inertia spaces

We introduce the notions of a differentiable groupoid and a differentiable stratified groupoid, generalizations of Lie groupoids in which the spaces of objects and arrows have the structures of differentiable spaces, respectively differentiable stratified spaces, compatible with the groupoid structure. After studying basic properties of these groupoids including Morita equivalence, we prove a de Rham theorem for locally contractible differentiable stratified groupoids. We then focus on the study of the inertia groupoid associated to a proper Lie groupoid. We show that the loop and the inertia space of a proper Lie groupoid can be endowed with a natural Whitney B stratification, which we call the orbit Cartan type stratification. Endowed with this stratification, the inertia groupoid of a proper Lie groupoid becomes a locally contractible differentiable stratified groupoid

OPserver: interactive online-computations of opacities and radiative accelerations

Codes to compute mean opacities and radiative accelerations for arbitrary chemical mixtures using the Opacity Project recently revised data have been restructured in a client--server architecture and transcribed as a subroutine library. This implementation increases efficiency in stellar modelling where element stratification due to diffusion processes is depth dependent, and thus requires repeated fast opacity reestimates. Three user modes are provided to fit different computing environments, namely a web browser, a local workstation and a distributed grid.Comment: 5 pages, 1 figur

Periodic Points and Sharkovsky’s Theorem

The number of periodic points of a function depends on the context. The number of complex periodic points and rational periodic points have been shown to be infinite and finite, respectively, if f is a polynomial of degree at least 2. However, the number of real periodic points can be either finite or infinite. Sharkovskys Theorem states that if p is left of q in the “Sharkovsky ordering” and the continuous function f has a point of period p, then f also has a point of period q. This statement becomes very powerful when considering a function that has points of period 3, all the way to the left side of the Sharkovsky ordering, since having a point of period 3 implies the existence of points of all periods. We explore a continuous function with points of period 3 where the function can be restricted to an interval containing points of period all other natural numbers

Multiwavelength Monitoring of the Dwarf Seyfert 1 Galaxy NGC 4395. IV. The Variable UV Absorption Lines

We report the detection of variable UV absorption lines in NGC 4395, based on UV observations with the HST STIS carried out in April and July, 2004, as part of a reverberation-mapping campaign. Low-ionization lines of O I, N I, Si II, C II, and Fe II, are present in the low-state spectra (April 2004) at a velocity v_shift=-250 km/s (system A_l), and additional high-ionization lines of C IV and N V appear in the high-state spectra (July 2004) at v_shift=-250 km/s (system A_h) and at v_shift=-840 km/s (system B). The absence of absorption from the low metastable levels of Si II implies a density <~10^3 cm^(-3) for system A_l, indicating a location outside the narrow line region (NLR). System A_h is peculiar as only N V absorption is clearly detected. A high N V/C IV absorption ratio is expected for a high metallicity absorber, but this is excluded here as the metallicity of the host galaxy and of the nuclear gas is significantly subsolar. A simple acceptable model for systems A_h and B is an absorber located between the broad line region (BLR) and the NLR, which absorbs only the continuum and the BLR. At the low-state the strong narrow emission lines of C IV and N V dominate the spectrum, making the absorption invisible. At the high-state the absorbed continuum and BLR emission dominate the spectrum. Thus, the change in the observed absorption does not reflect a change in the absorber, but rather a change in the continuum and BLR emission from behind the absorber, relative to the emission from the NLR in front of the absorber. Studies of the absorption line variability in highly variable objects can thus break the degeneracy in the absorber distance determination inherent to single epoch studies.Comment: Accepted for publication in The Astrophysical Journa