Effects of Metallicity on the Rotation Rates of Massive Stars

Recent theoretical predictions for low metallicity massive stars predict that these stars should have drastically reduced equatorial winds (mass loss) while on the main sequence, and as such should retain most of their angular momentum. Observations of both the Be/(B+Be) ratio and the blue-to-red supergiant ratio appear to have a metallicity dependence that may be caused by high rotational velocities. We have analyzed 39 archival Hubble Space Telescope Imaging Spectrograph (STIS), high resolution, ultraviolet spectra of O-type stars in the Magellanic Clouds to determine their projected rotational velocities V sin i. Our methodology is based on a previous study of the projected rotational velocities of Galactic O-type stars using International Ultraviolet Explorer (IUE) Short Wavelength Prime (SWP) Camera high dispersion spectra, which resulted in a catalog of V sin i values for 177 O stars. Here we present complementary V sin i values for 21 Large Magellanic Cloud and 22 Small Magellanic Cloud O-type stars based on STIS and IUE UV spectroscopy. The distribution of V sin i values for O type stars in the Magellanic Clouds is compared to that of Galactic O type stars. Despite the theoretical predictions and indirect observational evidence for high rotation, the O type stars in the Magellanic Clouds do not appear to rotate faster than their Galactic counterparts.Comment: accepted by ApJ, to appear 20 December 2004 editio

Making a difference - the appropriate use of web technology

Much has been written elsewhere about how, different Information Technology tools, can in principle be used by groups or communities to make their web sites more effective for Continued Professional Development. In practice, complex use is not often the case. In particular, three sites were studied in Scotland, which provided web facilities for the over 60s. The sites, and the communities they served, used only simple Information Technology. Nevertheless, they enabled their communities to participate effectively, on the 'right side', of the European population's 'digital divide'

(2,3,7,8,12,13,17,18-Octa­ethyl­por­phin­ato)(trifluoro­methane­sulfonato)iron(III)

The title compound, [Fe(CF3O3S)(C36H44N4)], is an iron(III) porphyrin complex with the trifluoro­methane­sulfonate anion as an axial ligand. The Fe atom is displaced by 0.219 (2) Å toward the trifluoro­methane­sulfonate anion from the 24-atom mean plane of the porphyrin, resulting in a distorted FeN4O square-based pyramidal geometry. One ethyl­ene group is disordered over two orientations in a 0.502 (6):0.498 (6) ratio

Reader Categorization of a Controversial Communication: Advertisement Versus Editorial

Using a disguised, structured technique, the authors collected consumer judgments regarding an editorial advertisement entitled Of cigarettes and science sponsored by R. J. Reynolds Tobacco Company. Respondents were shown an actual newspaper section that contained different types of editorials and advertisements, including the Of cigarettes and science item. After the respondents indirectly classified each item as either an editorial or advertisement, they were asked to list at least two characteristics about the appearance or wording of the Of cigarettes and science item that caused them to classify it as they did. The majority of respondents thought the item was an advertisement because it looked different from editorial items, was sponsored by R. J. Reynolds Tobacco Company, and seemed to have a persuasive or promotional content. Over one-fourth of the respondents, however, identified the communication as an editorial because of its lack of direct sales information and its extensive wording. The authors contend that legal and regulatory bodies should consider the effects of both source and intent of the message when arguing consumer impact

[5,10,15,20-Tetra­kis(4-meth­oxy­phen­yl)porphyrinato-κ4 N,N′,N′′,N′′′](trifluoro­methane­sulfonato-κO)­iron(III)

The title compound, [Fe(CF3O3S)(C48H36N4O4)], is a five-coordinate iron(III) porphyrin complex with a trifluoro­methane­sulfonate anion as an axial ligand. The FeIII atom is displaced by 0.40 (1) Å towards the trifluoro­methane­sulfonate anion from the 24-atom mean plane of the porphyrin. The average Fe—Np distance is 2.044 (2) Å and the Fe—O distance is 2.001 (2) Å

From Wasting to Obesity: The Contribution of Nutritional Status to Immune Activation in HIV Infection.

The impact of human immunodeficiency virus (HIV) infection on innate and adaptive immune activation occurs in the context of host factors, which serve to augment or dampen the physiologic response to the virus. Independent of HIV infection, nutritional status, particularly body composition, affects innate immune activation through a variety of conditions, including reduced mucosal barrier defenses and microbiome dysbiosis in malnutrition and the proinflammatory contribution of adipocytes and stromal vascular cells in obesity. Similarly, T-cell activation, proliferation, and cytokine expression are reduced in the setting of malnutrition and increased in obesity, potentially due to adipokine regulatory mechanisms restraining energy-avid adaptive immunity in times of starvation and exerting a paradoxical effect in overnutrition. The response to HIV infection is situated within these complex interactions between host nutritional health and immunologic function, which contribute to the varied phenotypes of immune activation among HIV-infected patients across a spectrum from malnutrition to obesity

Dinitro­sylbis[tris­(4-chloro­phen­yl)phosphane]iron

The title dinitrosyl iron diphosphane complex, [Fe(NO)2(C18H12Cl3P)2] or Fe(NO)2 L 2 [L = P(C6H4-p-Cl)3] belongs to the family of metal dinitrosyl compounds with the general formula Fe(NO)2(L)x, referred to collectively as dinitrosyl iron compounds (DNICs). The iron atom is tetra­hedrally coordinated by two phosphane ligands and two NO groups with Fe—N—O bond angles of 178.76 (15) and 177.67 (14)°

(Ethanolato)[2,3,7,8,12,13,17,18-octa­ethylporphyrinato(2−)]iron(III)

The title compound, [Fe(C2H5O)(C36H44N4)], contains a five-coordinate iron–porphyrin complex with an axial eth­oxy ligand. The iron(III) atom is displaced by 0.504 (2) Å towards the eth­oxy ligand from the 24-atom mean plane of the porphyrin. The average Fe—Np distance is 2.078 (2) Å and the Fe—O distance is 1.8232 (18) Å. The eth­oxy C atoms are disordered in a 0.581 (12):0.419 (12) ratio. The bond angles of the Fe—O—C linkage are 128.6 (3) and 130.4 (3)°, respectively, for the major and minor occupancy C atoms

Chloridonitros­yl[meso-5,10,15,20-tetra­kis­(p-tol­yl)porphyrinato-κ4 N,N′,N′′,N′′′]osmium(II) tetra­hydro­furan tetra­solvate

The title compound, [OsCl(NO)(C48H36N4)]·4C4H8O, is a six-coordinate osmium(II) porphyrin complex with nitrosyl (NO) and chloride (Cl) ligands trans to each other in an octa­hedral geometry. The metal complex lies on a fourfold rotation axis that passes through the Os, N, O and Cl atoms. The NO and Cl ligands are disordered in an 0.511 (12):0.486 (12) ratio

Methyl 9H-xanthene-9-carboxyl­ate

The title compound, C15H12O3, was obtained unintentionally as the by-product of an attempted recrystallization from methanol of propantheline bromide, an anti­muscarinic drug. The xanthone unit is folded, with a dihedral angle of 24.81 (9)° between the benzene rings. The ester substituent adopts a trans staggered conformation, with a C—C—O—C torsion angle of 178.4 (1)°. The mol­ecules pack in distinct layers, facilitated by C—H⋯π and weak π–π ring inter­actions. A weak C—H⋯O inter­action also occurs; however, no classical hydrogen bonding is observed