Correlation between Infrared Colors and Intensity Ratios of SiO Maser Lines

We present the results of SiO millimeter-line observations of a sample of known SiO maser sources covering a wide dust-temperature range. A cold part of the sample was selected from the SiO maser sources found in our recent SiO maser survey of cold dusty objects. The aim of the present research is to investigate the causes of the correlation between infrared colors and SiO maser intensity ratios among different transition lines. In particular, the correlation between infrared colors and SiO maser intensity ratio among the J=1-0 v=1, 2, and 3 lines are mainly concerned in this paper. We observed in total 75 SiO maser sources with the Nobeyama 45m telescope quasi-simultaneously in the SiO J=1-0 v=0, 1, 2, 3, 4 and J=2-1 v=1, 2 lines. We also observed the sample in the 29SiO J=1-0 v=0 and J=2-1 v=0, and 30SiO J=1-0 v=0 lines, and the H2O 6(1,6)-5(2,3) line. As reported in previous papers, we confirmed that the intensity ratios of the SiO J=1-0 v=2 to v=1 lines clearly correlate with infrared colors. In addition, we found possible correlation between infrared colors and the intensity ratios of the SiO J=1-0 v=3 to v=1&2 lines. Two overlap lines of H2O (i.e., 11(6,6) nu_2=1 -> 12(7,5) nu_2=0 and 5(0,5) nu_2=2 -> 6(3,4) nu_2=1) might explain these correlation if these overlap lines become stronger with increase of infrared colors, although the phenomena also might be explained by more fundamental ways if we take into account the variation of opacity from object to object.Comment: 49 pages, 7 figures, 3 tables, accepted for publication in ApJ. Full resolution version available at http://www.asiaa.sinica.edu.tw/~junichi/paper

Prolific pair production with high-power lasers

Prolific electron-positron pair production is possible at laser intensities approaching 10^{24} W/cm^2 at a wavelength of 1 micron. An analysis of electron trajectories and interactions at the nodes (B=0) of two counter-propagating, circularly polarised laser beams shows that a cascade of gamma-rays and pairs develops. The geometry is generalised qualitatively to linear polarisation and laser beams incident on a solid target.Comment: 4 pages, 1 figure, minor revisions, accepted for publication in Physical Review Letter

Identification of Very Red Counterparts of SiO Maser and OH/IR Objects in the GLIMPSE Survey

Using the 3.6/4.5/5.8/8.0 micron images with 1.2 arcsec pixel resolution from the Spitzer/GLIMPSE survey, we investigated 23 masing and 18 very red objects that were not identified in the 2MASS survey. Counterparts for all selected objects were found in the GLIMPSE images. Color indices in these IR bands suggest the presence of a high-extinction layer of more than a few tenths of a solar mass in front of the central star. Furthermore, radio observations in the SiO and H2O maser lines found characteristic maser-line spectra of the embedded objects, e.g., the SiO J=1-0 line intensity in the v=2 state stronger than that of the v=1 state, or very widespread H2O maser emission spectra. This indicates that these objects are actually enshrouded by very thick circumstellar matter, some of which cannot be ascribed to the AGB wind of the central star. Individually interesting objects are discussed, including two newly found water fountains and an SiO source with nebulosity.Comment: High resolution figures available at ftp://ftp.nro.nao.ac.jp/nroreport/no653.pdf.gz. ApJ No. 655 no.1 issue in pres

Nuclear electric propulsion stage requirements and description

The application of a nuclear electric propulsion (NEP) stage in the exploration of near-earth, cometary, and planetary space was discussed. The NEP stage is powered by a liquid-metal-cooled, fast spectrum thermionic reactor capable of providing 120 kWe for 20,000 hours. This power is used to drive a number of mercury ion bombardment thrusters with specific impulse in the range of 4000-5000 seconds. The NEP description, characteristics, and functional requirements are discussed. These requirements are based on a set of five coordinate missions, which are described in detail. These five missions are a representative part of a larger set of missions used as a basic for an advanced propulsion comparison study. Additionally, the NEP stage development plan and test program is outlined and a schedule presented

Self-reported health-related quality of life in persons with HIV infection: results from a multi-site interview project

BACKGROUND: To examine demographic and behavioral associations with self-reported health-related quality of life (HRQOL) among persons with HIV infection or AIDS. METHODS: Analysis of interviews with persons ≥ 18 years of age reported through routine disease surveillance with HIV infection or AIDS to nine state and local health departments from January 1995 through December 1996. Scales were constructed from validated measures of HRQOL, and mean scores were calculated (lower scores signified poorer HRQOL). Measures of HRQOL included Overall Health, Pain, Physical Functioning, Role Functioning, Social Functioning, Mental Health, Energy/Fatigue, and Cognitive Functioning. Differences in HRQOL were examined by various demographic and behavioral factors, including taking antiretroviral medication. RESULTS: HRQOL data were available for 3778 persons. Factors associated with lower HRQOL scores included older age, female sex, black or Hispanic race/ethnicity, injection drug use, lower education and income, no private health insurance, and lower CD4 count. In multivariate analysis, lower CD4 count was the factor most consistently associated with lower HRQOL. Taking antiretroviral medication was not associated with differences in HRQOL regardless of CD4 count. CONCLUSIONS: Perception of HRQOL varied in a population with HIV infection or AIDS. On most HRQOL measures, lower CD4 count was associated with lower HRQOL. Measurement of HRQOL can assist in understanding the long-term effects of disease and treatment on persons with HIV

Alternativity and reciprocity in the Cayley-Dickson algebra

We calculate the eigenvalue \rho of the multiplication mapping R on the Cayley-Dickson algebra A_n. If the element in A_n is composed of a pair of alternative elements in A_{n-1}, half the eigenvectors of R in A_n are still eigenvectors in the subspace which is isomorphic to A_{n-1}. The invariant under the reciprocal transformation A_n \times A_{n} \ni (x,y) -> (-y,x) plays a fundamental role in simplifying the functional form of \rho. If some physical field can be identified with the eigenspace of R, with an injective map from the field to a scalar quantity (such as a mass) m, then there is a one-to-one map \pi: m \mapsto \rho. As an example, the electro-weak gauge field can be regarded as the eigenspace of R, where \pi implies that the W-boson mass is less than the Z-boson mass, as in the standard model.Comment: To be published in J. Phys. A: Mathematical and Genera

Coexistence but Independent Biosynthesis of Catechyl and Guaiacyl/Syringyl Lignin Polymers in Seed Coats

Lignins are phenylpropanoid polymers, derived from monolignols, commonly found in terrestrial plant secondary cell walls. We recently reported evidence of an unanticipated catechyl lignin homopolymer (C lignin) derived solely from caffeyl alcohol in the seed coats of several monocot and dicot plants. We previously identified plant seeds that possessed either C lignin or traditional guaiacyl/syringyl (G/S) lignins, but not both. Here, we identified several dicot plants (Euphorbiaceae and Cleomaceae) that produce C lignin together with traditional G/S lignins in their seed coats. Solution-state NMR analyses, along with an in vitro lignin polymerization study, determined that there is, however, no copolymerization detectable (i.e., that the synthesis and polymerization of caffeyl alcohol and conventional monolignols in vivo is spatially and/or temporally separated). In particular, the deposition of G and C lignins in Cleome hassleriana seed coats is developmentally regulated during seed maturation; C lignin appears successively after G lignin within the same testa layers, concurrently with apparent loss of the functionality of O-methyltransferases, which are key enzymes for the conversion of C to G lignin precursors. This study exemplifies the flexible biosynthesis of different types of lignin polymers in plants dictated by substantial, but poorly understood, control of monomer supply by the cells

Autoregulation of cochlear blood flow in young and aged mice

Autoregulation is the capacity of an organ system to maintain organ blood flow constant in response to changes in arterial blood pressure (BP). The current study was carried out to investigate the effect of age on autoregulation of cochlear blood flow (CBF) in mice. CBF was measured using a laser-Doppler flowmeter while BP was increased by angiotensin 11 injections and decreased by exsanguination in 2-month-old, 10-month-old and 18-month-old CBA mice. Autoregulation of CBF was significantly weaker in the 2-month-old mice when compared to the older mice. Although CBF autoregulation was weaker in the 18-month-old mice compared to the 10-month-old mice, this difference was not statistically significant. These results suggest that autoregulation changes with maturation and age. Findings are discussed in relationship to the possible development of presbycusis.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47278/1/405_2004_Article_BF00185395.pd