Ultraviolet Radiation from Evolved Stellar Populations: II. The Ultraviolet Upturn Phenomenon in Elliptical Galaxies

We present an analysis of the far-ultraviolet upturn phenomenon (UVX) observed in elliptical galaxies and spiral galaxy bulges. Our premise is that the UV radiation from these systems emanates primarily from extreme horizontal branch (EHB) stars and their progeny. We re-derive the broad-band UV colors $1500-V$ and $2500-V$ for globular clusters and elliptical galaxies from the available satellite data and investigate color-color and color-line strength correlations. We also provide the ingredients necessary for constructing models with arbitrary HB morphologies.Comment: uuencoded compressed postscript file, 60pp. (revisions on pp. 7,8,22,33,37 & 57

Rethinking our understanding of the pathogenesis of necrotic enteritis in chickens

For decades, low doses of antibiotics have been used widely in animal production to promote growth. However, there is a trend to reduce this use of antibiotics in feedstuffs, and legislation is now in place in Europe to prohibit their use in this way. As a consequence, economically important diseases, such as necrotic enteritis (NE) of chickens, that are caused by Clostridium perfringens have become more prevalent. Recent research is creating a paradigm shift in our understanding of the pathogenesis of NE and is now providing information that will be necessary to monitor and control the incidence of NE in poultry

Recent Legal Literature

Abbott: Brief upon the Pleadings in Civil Actions, at Law in Equity, and under the New Procedure; McMaster: McMaster\u27s Irregular and Regular Commercial Paper; American State Reports, vols. 93 and 94

A Superwind from Early Post-Red Giant Stars?

We suggest that the gap observed at 20,000 K in the horizontal branches of several Galactic globular clusters is caused by a small amount of extra mass loss which occurs when stars start to "peel off" the red giant branch (RGB), i.e., when their effective temperature starts to increase, even though they may still be on the RGB. We show that the envelope structure of RGB stars which start to peel off is similar to that of late asymptotic giant branch stars known to have a super-wind phase. An analogous super-wind in the RGB peel-off stars could easily lead to the observed gap in the distribution of the hottest HB stars.Comment: 9 pages; Accepted by ApJ Letters; Available also at http://www.astro.puc.cl/~mcatelan

UV Properties of Galactic Globular Clusters with GALEX II. Integrated colors

We present ultraviolet (UV) integrated colors of 44 Galactic globular clusters (GGCs) observed with the Galaxy Evolution Explorer (GALEX) in both FUV and NUV bands. This data-base is the largest homogeneous catalog of UV colors ever published for stellar systems in our Galaxy. The proximity of GGCs makes it possible to resolve many individual stars even with the somewhat low spatial resolution of GALEX. This allows us to determine how the integrated UV colors are driven by hot stellar populations, primarily horizontal branch stars and their progeny. The UV colors are found to be correlated with various parameters commonly used to define the horizontal branch morphology. We also investigate how the UV colors vary with parameters like metallicity, age, helium abundance and concentration. We find for the first time that GCs associated with the Sagittarius dwarf galaxy have (FUV-V) colors systematically redder than GGCs with the same metallicity. Finally, we speculate about the presence of an interesting trend, suggesting that the UV color of GCs may be correlated with the mass of the host galaxy, in the sense that more massive galaxies possess bluer clusters.Comment: Accepted for publication by The Astronomical Journal. 36 pages, 9 figures, 1 tabl

Solid expellant plasma generator

An improved solid expellant plasma generator has been developed. The plasma generator includes a support housing, an electrode rod located in the central portion of the housing, and a mass of solid expellant material that surrounds the electrode rod within the support housing. The electrode rod and the solid expellant material are made of separate materials that are selected so that the electrode and the solid expellant material decompose at the same rate when the plasma generator is ignited. This maintains a point of discharge of the plasma at the interface between the electrode and the solid expellant material

The Origin of Extreme Horizontal Branch Stars

Strong mass loss on the red giant branch (RGB) can result in the formation of extreme horizontal branch (EHB) stars. The EHB stars spend most of their He core and shell burning phase at high temperatures and produce copious ultraviolet flux. They have very small hydrogen envelopes and occupy a small range in mass. We have computed evolutionary RGB models with mass loss for stars with a range of metallicities at initial masses < 1.1 Msun corresponding to populations ages between 12.5 and 14.5 Gyr. We used the Reimers formula to characterize mass loss, but investigated a larger range of the mass loss efficiency parameter, eta, than is common. To understand how the number of EHB stars varies with metallicity in a stellar population we considered how the zero-age horizontal branch (ZAHB) is populated. The range in eta producing EHB stars is comparable to that producing `mid-HB' stars. Somewhat surprisingly, neither the range nor magnitude of eta producing EHB stars varies much metallicity. In contrast, the range of eta producing mid-HB stars decreases with increasing metallicity. Hence the HB of populations with solar metallicity and higher, such as expected in elliptical galaxies and spiral bulges, will be bimodal if the distribution covers a sufficiently large range in eta.Comment: AASLaTeX v.4, 29pp., postscript available at http://shemesh.gsfc.nasa.gov/~dorman/Ben.htm

Mach 6 electroformed nickel nozzle refurbishment: FNAS investigation of ultra-smooth surfaces

The task objective has been to apply a coating of nickel-phosphorous alloy to a laminar flow wind tunnel nozzle by catalytic deposition and then polish and inspect the inside surface using optical device processes. The surface of the nozzle was coated with a nickel-phosphorous alloy of sufficient hardness and corrosion resistance to improve the durability. Due to plating defects that were clearly process related and not inherent, the final polished part was less than the desired quality. Surface finishing processes and lapping media were identified which produced a submicron surface finish on the interior plated surface. Defects apparently manifested by the first plating attempt were repaired using a small brush plating process demonstrating that individual small defects can be repaired. Measurement and analysis by profilometry demonstrated that quantitative control of the surface can be achieved

The Importance of Shared Language in Rural Behavioral Health Interventions: An Exploratory Linguistic Analysis

A focus on the use of shared language to enhance congruence in interventionist-client dialogue is missing from traditional research on evidence-based practices and rural behavioral health. This study incorporates qualitative interactional sociolinguistics, which includes discourse analysis (typically written or audio recordings of face-to-face encounters with 11 clients and a study interventionist), to describe those speech patterns in a broad sense (dialect), as well as more specific use of communicative strategies to increase parity in the interaction between a rural interventionist delivering an evidence-based practice in the context of a research study with rural women opioid users in a non-therapeutic context. Study findings indicated that in the context of delivering the intervention, use of a shared language, language pattern congruence, and communication styles can greatly augment the intent of the approach with vulnerable populations. In addition, other communicative strategies connected with traditional Appalachian values – such as religion, home, and family – were also important. This study makes an important contribution to behavioral health research and practice by understanding critical factors that may influence evidence-based practice delivery, particularly in real-world settings with vulnerable populations. These findings have important implications for the utilization of creative approaches to understand critical components of the clinical interaction as indicators of fidelity