ISO LWS Spectroscopy of M82: A Unified Evolutionary Model

We present the first complete far-infrared spectrum (43 to 197 um) of M82, the brightest infrared galaxy in the sky, taken with the Long Wavelength Spectrometer of the Infrared Space Observatory (ISO). We detected seven fine structure emission lines, [OI] 63 and 145 um, [OIII] 52 and 88 um, [NII] 122 um, [NIII] 57 um and [CII] 158 um, and fit their ratios to a combination starburst and photo-dissociation region (PDR) model. The best fit is obtained with HII regions with n = 250 cm^{-3} and an ionization parameter of 10^{-3.5} and PDRs with n = 10^{3.3} cm^{-3} and a far-ultraviolet flux of G_o = 10^{2.8}. We applied both continuous and instantaneous starburst models, with our best fit being a 3-5 Myr old instantaneous burst model with a 100 M_o cut-off. We also detected the ground state rotational line of OH in absorption at 119.4 um. No excited level OH transitions are apparent, indicating that the OH is almost entirely in its ground state with a column density ~ 4x10^{14} cm^{-2}. The spectral energy distribution over the LWS wavelength range is well fit with a 48 K dust temperature and an optical depth, tau_{Dust} proportional to lambda^{-1}.Comment: 23 pages, 4 figures, accepted by ApJ, Feb. 1, 199

HI Narrow Self-Absorption in Dark Clouds: Correlations with Molecular Gas and Implications for Cloud Evolution and Star Formation

We present the results of a comparative study of HI narrow self-absorption (HINSA), OH, 13CO, and C18O in five dark clouds. The HINSA follows the distribution of the emission of the carbon monoxide isotopologues, and has a characteristic size close to that of 13CO. This confirms that the HINSA is produced by cold HI which is well mixed with molecular gas in well-shielded regions. The ratio of the atomic hydrogen density to total proton density for these sources is 5 to 27 x 10^{-4}. Using cloud temperatures and the density of HI, we set an upper limit to the cosmic ray ionization rate of 10^{-16} s^{-1}. Comparison of observed and modeled fractional HI abundances indicates ages for these clouds to be 10^{6.5} to 10^{7} yr. The low values of the HI density we have determined make it certain that the time scale for evolution from an atomic to an almost entirely molecular phase, must be a minimum of several million years. This clearly sets a lower limit to the overall time scale for star formation and the lifetime of molecular clouds

Phase-Referenced VLBA Observations of OH Masers at 4765 MHz

We report VLBA observations of maser emission from the rotationally excited doublet Pi 1/2, J=1/2 state of OH at 4765 MHz. We made phase-referenced observations of W3(OH) at both 4765 MHz and 1720 MHz and found emission in three fields within a about 2000 AU diameter region and verified that in two of the three fields, 4765 MHz and 1720 MHz emission arise from the same position to within about 4 mas (about 5 AU diameter emission regions along an approximately N-S arc with linear extent about 500 AU. In addition, we carried out phase-referenced observations of 4765 MHz emission from K3-50. We searched for the 4765 MHz line in W49 (without phase referencing) and W75N (phase-referenced to the strongest 4765 MHz maser feature in DR21EX); we were unable to detect these sources with the VLBA. For 2 1/2 years (including the dates of the VLBA observations), we carried out monitoring observations of 4765 MHz emission with the VLA. Constraints on models for maser emission at 1720 MHz and 4765 MHz are derived from the observations. These observations are then briefly compared with existing models.Comment: 30 pages, 7 figures, to be published in Ap. J. (Dec 10, 2003

Histological and microbiological aspects of actinomycetoma cases in Venezuela

A ten year (1976-1986) review study of cases of Actinomycetoma in Venezuela was made through personal interview and clinical examinations, analysis of medical records of patients with actinomycetoma, histological studies of biopsy samples, as well as microbiological studies of isolates strain, also through out personal interviews with researchers and dermatologists who were sources of information on mycetoma cases. A total of 47 cases were recorded. As etiologic agent Actinomadura madurae was found in 20 cases - (42.5%), Nocardia brasiliensis in 13 cases (27.6%), Nocardia spp 7 cases (14.8%), Streptomyces somaliensis in 4 cases (8.5%), N. asteroides in 2 cases (4.2%) and N. otitidis caviarum, (N. caviae) in 1 case (2.1%). Most of the reported cases involved individuals living and working in rural areas, mostly males who outnumber females 4:1. The patients were 18 to 80 years old. A. madurae was reported as the most frequent etiologic agent. Most of the clinical cases were seen when the disease was well established. Twenty four of the forty seven cases reported were observed in Lara State, which represents a 51.0% of all the cases studied

Les variations semi-diurnes dans le débit des concrétions à Sainte-Eulalie-en-Royans

Résumé. — Grâce à un système expérimental, une série de mesures sur le débit des concrétions a été effectuée dans la grotte du Sourcier à Sainte-Eulalie-en-Royans. Les premiers résultats montrent diverses variations de débit dont la plus originale est semi-diurne. Diverses hypothèses sont avancées.Destombes J.-L., Delannoy J.-J. Les variations semi-diurnes dans le débit des concrétions à Sainte-Eulalie-en-Royans. In: Revue de géographie alpine, tome 68, n°3, 1980. pp. 255-266

INFRARED DIODE LASER SPECTRA OF MgH, MgD, CaH AND CaDX2Σ+CaD X {^{2}}\Sigma^{+}

Author Institution:Rotation-vibration spectra of MgH, CaH and their deuterated forms in the $X {^2{\Sigma}^{+}}$ state have been measured using tunable infrared diode lasers. The hydrides were produced in a D.C. discharge of $H_{2}$ or $D_{2}$ over heated magnesium or calcium. Transitions from the fundamental bands and from hot bands $(v=2\leftarrow 1$ for MgH, and up to $v=4 \leftarrow 3$ for CaH) were observed. The spectra were analyzed to determine accurate set of molecular parameters, either for each vibrational state or as Dunham coefficients. The mass dependance of the molecular parameters is examined in terms of possible breakdown of the Born-Oppenheimer approximation

SUBSTITUTION STRUCTURE OF THE CCH RADICAL FROM THE ANALYSIS OF THE ROTATIONAL SPECTRA OF VARIOUS ISOTOPIC FORMS.

Author Institution: Universit\'{e} de Lille-Flandres-Artois, Laboratoire de Spectroscopie Hertzienne, associ\'{e} au CNRSThe submillimeter wave spectra of $^{13}CCH$ and $C^{13}CH$ were recently observed inside a R.F. glow discharge in a mixture of $^{13}CO, CH_{4}$ and He. Accurate molecular constants were derived, and the frequencies of the lines of astrophysically interest were predicted. Using the previously determined rotational constants of CCH and CCD together with those determined in this work, a substitution structure was determined and compared to ab initio calculations

PRESSURE BROADENING OF HYDROXYL RADICAL MICROWAVE SPECTRUM

Author Institution: Laboratoire de Spectroscopie Hertzienne, C.N.R.S., Universit\'{e} de Lille IThe pressure broadeninig of the $J = 9/2, F = 4 \rightarrow$ 4 and $F = 5 \rightarrow 5$ A doubling transitions of the OH radical in the $^{2}M_{3/2}$ state has been investigated with a source modulation spectrometer. Results are given for collisions with foreign gases $NO_{2}$ and $H_{2}O$. Experimental problems of such measurements, caused essentially by the rather complex mixture composition, are discussed

MEASUREMENT BY MILLIMETER-WAVE SPECTROSCOPY OF TUNNELING SPLITTING FOR THE NON-CLASSICAL FORM OF C2HC_{2}H3+3^{+}

(1) M.W. Crofton, M.F. Jagod, B.D. Rehfuss and T. Oka, J. Chem. Phys. 91, 5139 (1989). (2) M. Bogey, M. Cordonnier, C. Demuynck and J.L. Destombes, Astrophys. J. 399, 103 (1992). (3) R. Escribano, private communication (1993)Author Institution: Laboratoire de Spectroscopie Hertzienne, U.F.R. de Physique. Universit\'{e} de Lille I; Department of Chemistry, University of ChicagoThe non-classical form (bridged) of the protonated acetylene $C_{2}H_{3}^{+}$ has now been identified both by IR (1) and MW (2) spectroscopy. The analysis of the $\nu_{6}$ vibrational state led the evidence of the exchange of the three protons in a tunneling rearrangement of this structure through its classical isomer (1). We report our observation of the splittings of the A-E energy levels in the ground state using millimeter wave spectroscopy. Recent improvements of our spectrometer have increased its performance. We are now able to measure accurately the splitting of the $1_{1.0} \leftarrow 1_{0,1}$ and $3_{1,2}\leftarrow 3_{0,3}$ transitions. The obtained values are within the predictions of Escribano with a barrier of about $1600 cm^{-1}$ (3). However, up to now, the theoretical model does not fit precisely to the experimental data