Coronae of Stars with Super Solar Elemental Abundances

Coronal elemental abundances are known to deviate from the photospheric values of their parent star, with the degree of deviation depending on the First Ionization Potential (FIP). This study focuses on the coronal composition of stars with super-solar photospheric abundances. We present the coronal abundances of six such stars: 11 LMi, $\iota$ Hor, HR 7291, $\tau$ Boo, and $\alpha$ Cen A and B. These stars all have high-statistics X-ray spectra, three of which are presented for the first time. The abundances measured in this paper are obtained using the line-resolved spectra of the Reflection Grating Spectrometer (RGS) in conjunction with the higher throughput EPIC-pn camera spectra on board the XMM-Newton observatory. A collisionally ionized plasma model with two or three temperature components is found to represent the spectra well. All elements are found to be consistently depleted in the coronae compared to their respective photospheres. For 11 LMi and $\tau$ Boo no FIP effect is present, while $\iota$ Hor, HR 7291, and $\alpha$ Cen A and B show a clear FIP trend. These conclusions hold whether the comparison is made with solar abundances or the individual stellar abundances. Unlike the solar corona where low FIP elements are enriched, in these stars the FIP effect is consistently due to a depletion of high FIP elements with respect to actual photospheric abundances. Comparing to solar abundances (instead of stellar) yields the same fractionation trend as on the Sun. In both cases a similar FIP bias is inferred, but different fractionation mechanisms need to be invoked.Comment: 11 pages, 7 figures, submitted to A&A. Comments are welcom

Multi-wavelength Radio Continuum Emission Studies of Dust-free Red Giants

Multi-wavelength centimeter continuum observations of non-dusty, non-pulsating K spectral-type red giants directly sample their chromospheres and wind acceleration zones. Such stars are feeble emitters at these wavelengths however, and previous observations have provided only a small number of modest S/N measurements slowly accumulated over three decades. We present multi-wavelength Karl G. Jansky Very Large Array thermal continuum observations of the wind acceleration zones of two dust-free red giants, Arcturus (Alpha Boo: K2 III) and Aldebaran (Alpha Tau: K5 III). Importantly, most of our observations of each star were carried out over just a few days, so that we obtained a snapshot of the different stellar atmospheric layers sampled at different wavelengths, independent of any long-term variability. We report the first detections at several wavelengths for each star including a detection at 10 cm (3.0 GHz: S band) for both stars and a 20 cm (1.5 GHz: L band) detection for Alpha Boo. This is the first time single luminosity class III red giants have been detected at these continuum wavelengths. Our long-wavelength data sample the outer layers of Alpha Boo's atmosphere where its wind velocity is approaching its terminal value and the ionization balance is becoming frozen-in. For Alpha Tau, however, our long-wavelength data are still sampling its inner atmosphere, where the wind is still accelerating probably due to its lower mass-loss rate. We compare our data with published semi-empirical models based on ultraviolet data, and the marked deviations highlight the need for new atmospheric models to be developed. Spectral indices are used to discuss the possible properties of the stellar atmospheres, and we find evidence for a rapidly cooling wind in the case of Alpha Boo. Finally, we develop a simple analytical wind model for Alpha Boo based on our new long-wavelength flux measurements

Imaginative Involvement and Hypnotic Susceptibility

J. Hilgard (1970, 1972, 1974, 1979), utilizing an interview format, asserted that a personality variable, namely, an individual's capacity to become imaginatively involved in experiences outside of hypnosis, was significantly correlated with his or her hypnotic susceptibility. Tellegen and Atkinson (1974) operationalized the imaginative involvement variable in a 37-item questionnaire, the Tellegen Absorption Scale (TAS) that correlated significantly with hypnotic susceptibility (e.g., Crawford, 1982). However, Council, Kirsch, and Hafner (1986) suggested that the relationship between the TAS and hypnotic susceptibility is a context-mediated artifact in that the two correlate only when the TAS is administered within a context clearly identified as involving hypnosis. As the interviews conducted by J. Hilgard (1970, 1972, 1974, 1979) were done within a context clearly identified as involving hypnosis, the possibility exists that the relationship between imaginative involvement and hypnotic susceptibility is also a context-mediated artifact. In a test of this possibility, 86 subjects were interviewed concerning their imaginative involvements. Forty-three subjects were interviewed within a context defined as "research investigating hypnosis" and 43 subjects were interviewed within a context defined as "research investigating imagination." Hypnotic susceptibility was assessed in sessions separate from the interviews. In the present study, an individual's hypnotic susceptibility was not found to be significantly related to his or her imaginative involvement. It appears J. Hilgard's original finding may have been due to chance correlations compounded by subsequent experimenter expectancy effects. It is recommended that J. Hilgard's work be clarified through more extensive replications in which experimenter blindness is assured

Time-dependent release of iron from soot particles by acid extraction and the reduction of fe3+ by elemental carbon

Elemental carbon reduces Fe3+ to Fe2+ in aqueous solutions. This process has potential implications in the adverse health effects of fine particles in air pollution, because both elemental carbon and iron are major components in atmospheric particulate matter. In this study we measured the time-dependent release of iron from laboratory flames and standard reference soot particles that contained iron, and the reduction of Fe3+ to Fe2+ in an acid extraction process. The concentration of Fe3+ and Fe2+ ions in the extraction solutions was measured by a spectrophotometric method. The results showed that while Fe3+ was the dominant valence state in the dry soot particles, significant fraction of iron was reduced to Fe2+ in the aqueous solution. Further investigation is needed to assess the significance of this phenomenon in the biological effects of particles that contain iron and elemental carbon

Variable geometry inlet design for scram jet engine

The present invention relates to an improved variable geometry inlet for a scram jet engine having at least one combustor module. The variable geometry inlet comprises each combustor module having two sidewalls. Each of the sidewalls has a central portion with a thickness and a tapered profile forward of the central portion. The tapered profile terminates in a sharp leading edge. The variable geometry inlet further comprises each module having a lower wall and a movable cowl flap positioned forward of the lower wall. The movable cowl flap has a leading edge and the leading edges of the sidewalls intersect the leading edge of the cowl flap

Synergistic effect of co-exposure to carbon black and Fe2O3 nanoparticles on oxidative stress in cultured lung epithelial cells

BACKGROUND: There is a need to better understand synergism in the biological effects of particles composed of multiple substances. The objective of this study was to determine if the oxidative stress in cultured cells caused by co-exposure to carbon black and Fe(2)O(3 )nanoparticles was significantly greater than the additive effects of exposure to either type of particles alone; and to determine a possible cause for such synergistic effect if one was found. Cultured A549 human lung epithelial cells were exposed to (1) carbon black nanoparticles alone, (2) Fe(2)O(3 )nanoparticles alone, and (3) both types of particles simultaneously. Protein oxidation, lipid peroxidation, and cellular uptake of Fe in these cells were measured after 25 hours of exposure. The reduction of solubilized Fe(3+ )by the carbon black nanoparticles was measured separately in a cell-free assay, by incubating the carbon black and the Fe(2)O(3 )nanoparticles in 0.75 M sulfuric acid at 40°C and measuring the amount of reduced Fe(3+ )at different time points up to 24 hours. RESULTS: Cells exposed to carbon black particles alone did not show protein oxidation, nor did the cells exposed to Fe(2)O(3 )particles alone, relative to the control. However, cells co-exposed to both carbon black and Fe(2)O(3 )particles showed up to a two-fold increase in protein oxidation relative to the control. In addition, co-exposure induced significant lipid peroxidation, although exposure to either particle type alone did not. No significant difference in cellular iron uptake was found between single exposure and co-exposure, when the Fe(2)O(3 )dosing concentration was the same in each case. In the cell-free assay, significant reduction of Fe(3+ )ions by carbon black nanoparticle was found within 2 hour, and it progressed up to 24 hours. At 24 hours, the carbon black nanoparticles showed a reductive capacity of 0.009 g/g, defined as the mass ratio of reduced Fe(3+ )to carbon black. CONCLUSION: Co-exposure to carbon black and Fe(2)O(3 )particles causes a synergistic oxidative effect that is significantly greater than the additive effects of exposures to either particle type alone. The intracellular redox reaction between carbon black and Fe(3+ )is likely responsible for the synergistic oxidative effect. Therefore elemental carbon particles and fibres should be considered as potential reducing agents rather than inert materials in toxicology studies. Acidified cell organelles such as the lysosomes probably play a critical role in the solubilization of Fe(2)O(3). Further research is necessary to better understand the mechanisms

Caring for the Future: The Power and Potential of Americas Direct Care Workforce (Executive Summary)

This executive summary describes the key points of our comprehensive, current-day analysis of the direct care workforce. This report is the culmination of a year-long series of reports (released throughout 2020) providing a comprehensive, current-day analysis of the direct care workforce and its critical role in the long-term care system in the United States. By bringing these reports together, this final report provides: a detailed profile of these workers; a segmented look at the long-term care industry; a discussion on the evolving role of the direct care worker; a proposed framework for creating quality jobs in direct care; and a look forward at where this workforce and industry are heading. The report also offers concrete recommendations for policymakers, employers, advocates, and other long-term care leaders, and features stories of direct care workers from around the country, sharing their wisdom and ideas. In releasing this report, our goal is to strengthen the national dialogue on the direct care workforce, including what needs to change in policy and in practice

Caring for the Future: The Power and Potential of Americas Direct Care Workforce

This report is the culmination of a year-long series of reports (released throughout 2020) providing a comprehensive, current-day analysis of the direct care workforce and its critical role in the long-term care system in the United States. By bringing these reports together, this final report provides: a detailed profile of these workers; a segmented look at the long-term care industry; a discussion on the evolving role of the direct care worker; a proposed framework for creating quality jobs in direct care; and a look forward at where this workforce and industry are heading. The report also offers concrete recommendations for policymakers, employers, advocates, and other long-term care leaders, and features stories of direct care workers from around the country, sharing their wisdom and ideas. In releasing this report, our goal is to strengthen the national dialogue on the direct care workforce, including what needs to change in policy and in practice.workforce,including what needs to change in policy and in practice

A role for glycolipid biosynthesis in severe fever with thrombocytopenia syndrome virus entry

A novel bunyavirus was recently found to cause severe febrile illness with high mortality in agricultural regions of China, Japan, and South Korea. This virus, named severe fever with thrombocytopenia syndrome virus (SFTSV), represents a new group within the Phlebovirus genus of the Bunyaviridae. Little is known about the viral entry requirements beyond showing dependence on dynamin and endosomal acidification. A haploid forward genetic screen was performed to identify host cell requirements for SFTSV entry. The screen identified dependence on glucosylceramide synthase (ugcg), the enzyme responsible for initiating de novo glycosphingolipid biosynthesis. Genetic and pharmacological approaches confirmed that UGCG expression and enzymatic activity were required for efficient SFTSV entry. Furthermore, inhibition of UGCG affected a post-internalization stage of SFTSV entry, leading to the accumulation of virus particles in enlarged cytoplasmic structures, suggesting impaired trafficking and/or fusion of viral and host membranes. These findings specify a role for glucosylceramide in SFTSV entry and provide a novel target for antiviral therapies