The irradiated ISM of ULIRGs

The nuclei of ULIRGs harbor massive young stars, an accreting central black hole, or both. Results are presented for molecular gas that is exposed to X-rays (1-100 keV, XDRs) and far-ultraviolet radiation (6-13.6 eV, PDRs). Attention is paid to species like HCO+, HCN, HNC, OH, H2O and CO. Line ratios of HCN/HCO+ and HNC/HCN discriminate between PDRs and XDRs. Very high J (>10) CO lines, observable with HIFI/Herschel, discriminate very well between XDRs and PDRs. In XDRs, it is easy to produce large abundances of warm (T>100 K) H2O and OH. In PDRs, only OH is produced similarly well.Comment: 5 pages, 6 figures, to appear in: IAU Symposium 242 Astrophysical Masers and their Environment

Rhinosporidium seeberi: a human pathogen from a novel group of aquatic protistan parasites.

Rhinosporidium seeberi, a microorganism that can infect the mucosal surfaces of humans and animals, has been classified as a fungus on the basis of morphologic and histochemical characteristics. Using consensus polymerase chain reaction (PCR), we amplified a portion of the R. seeberi 18S rRNA gene directly from infected tissue. Analysis of the aligned sequence and inference of phylogenetic relationships showed that R. seeberi is a protist from a novel clade of parasites that infect fish and amphibians. Fluorescence in situ hybridization and R. seeberi- specific PCR showed that this unique 18S rRNA sequence is also present in other tissues infected with R. seeberi. Our data support the R. seeberi phylogeny recently suggested by another group. R. seeberi is not a classic fungus, but rather the first known human pathogen from the DRIPs clade, a novel clade of aquatic protistan parasites (Ichthyosporea)

Simultaneous Observations of GRS 1758-258 in 1997 by VLA, IRAM, SEST, RXTE and OSSE: Spectroscopy and Timing

We report the results of our multi-wavelength observations of GRS 1758-258 made in August 1997. The energy bands include radio, millimeter, X-ray, and gamma-ray. The observations enable us to obtain a complete spectrum of the source over an energy range of 2 - 500 keV. The spectrum shows that GRS 1758-258 was in its hard state. It is well fitted by the Sunyaev-Titarchuk (ST) Compton scattering model. The spectrum is also fit by a power law with an exponential cutoff (PLE) plus a soft black-body component. The temperature of the soft component is about 1.2 keV, and the energy flux is less than 1.5% of the total X- and gamma-ray flux. The deduced hydrogen column density is in the range of (0.93 - 2.0) 10^{22} cm^{-2}. No significant iron lines are detected. The radio emission has a flat energy spectrum. The daily radio, X-ray and gamma-ray light curves show that GRS 1758-258 was stable during the observation period, but was highly variable on smaller time scales in X- and gamma-rays. The power density spectra are typical for the low-state, but we find the photon flux for the 5 to 10 keV band to be more variable than that in the other two energy bands (2 - 5 keV and 10 - 40 keV). Harmonically spaced quasi-periodic oscillations (QPOs) are observed in the power spectra. The phase lags between the hard photons and the soft photons have a flat distribution over a wide range of frequencies. A high coherence of about 1.0 (0.01 - 1 Hz) between the hard photons and the soft photons is also obtained in our observations. We compare these results with two variation models. Our millimeter observations did not reveal any conclusive signatures of an interaction between the jet from GRS 1758-258 and the molecular cloud that lies in the direction of GRS 1758-258.Comment: 32 pages, 13 figures, to appear in ApJ, 2000, V.533, no. 1, Apr. 10. For better figure resolution, please directly download the paper from http://spacsun.rice.edu/~lin/publication.htm

Search for Interstellar Water in the Translucent Molecular Cloud toward HD 154368

We report an upper limit of 9 x 10^{12} cm-2 on the column density of water in the translucent cloud along the line of sight toward HD 154368. This result is based upon a search for the C-X band of water near 1240 \AA carried out using the Goddard High Resolution Spectrograph of the Hubble Space Telescope. Our observational limit on the water abundance together with detailed chemical models of translucent clouds and previous measurements of OH along the line of sight constrain the branching ratio in the dissociative recombination of H_3O+ to form water. We find at the $3\sigma$ level that no more than 30% of dissociative recombinations of H_3O+ can lead to H_2O. The observed spectrum also yielded high-resolution observations of the Mg II doublet at 1239.9 \AA and 1240.4 \AA, allowing the velocity structure of the dominant ionization state of magnesium to be studied along the line of sight. The Mg II spectrum is consistent with GHRS observations at lower spectral resolution that were obtained previously but allow an additional velocity component to be identified.Comment: Accepted by ApJ, uses aasp

Warm molecular hydrogen in the Spitzer SINGS galaxy sample

(simplified) Results on the properties of warm H2 in 57 normal galaxies are derived from H2 rotational transitions, obtained as part of SINGS. This study extends previous extragalactic surveys of H2, the most abundant constituent of the molecular ISM, to more common systems (L_FIR = e7 to 6e10 L_sun) of all morphological and nuclear types. The S(1) transition is securely detected in the nuclear regions of 86% of SINGS galaxies with stellar masses above 10^9.5 M_sun. The derived column densities of warm H2 (T > ~100 K), even though averaged over kiloparsec-scale areas, are commensurate with those of resolved PDRs; the median of the sample is 3e20 cm-2. They amount to between 1% and >30% of the total H2. The power emitted in the sum of the S(0) to S(2) transitions is on average 30% of the [SiII] line power, and ~4e-4 of the total infrared power (TIR) within the same area for star-forming galaxies, which is consistent with excitation in PDRs. The fact that H2 emission scales tightly with PAH emission, even though the average radiation field intensity varies by a factor ten, can also be understood if both tracers originate predominantly in PDRs, either dense or diffuse. A large fraction of the 25 LINER/Sy targets, however, strongly depart from the rest of the sample, in having warmer H2 in the excited states, and an excess of H2 emission with respect to PAHs, TIR and [SiII]. We propose a threshold in H2 to PAH power ratios, allowing the identification of low-luminosity AGNs by an excess H2 excitation. A dominant contribution from shock heating is favored in these objects. Finally, we detect, in nearly half the star-forming targets, non-equilibrium ortho to para ratios, consistent with FUV pumping combined with incomplete ortho-para thermalization by collisions, or possibly non-equilibrium PDR fronts advancing into cold gas.Comment: ApJS, in pres

On the source of the late-time infrared luminosity of SN 1998S and other type II supernovae

We present late-time near-infrared (NIR) and optical observations of the type IIn SN 1998S. The NIR photometry spans 333-1242 days after explosion, while the NIR and optical spectra cover 333-1191 days and 305-1093 days respectively. The NIR photometry extends to the M'-band (4.7 mu), making SN 1998S only the second ever supernova for which such a long IR wavelength has been detected. The shape and evolution of the H alpha and HeI 1.083 mu line profiles indicate a powerful interaction with a progenitor wind, as well as providing evidence of dust condensation within the ejecta. The latest optical spectrum suggests that the wind had been flowing for at least 430 years. The intensity and rise of the HK continuum towards longer wavelengths together with the relatively bright L' and M' magnitudes shows that the NIR emission was due to hot dust newly-formed in supernovae may provide the ejecta and/or pre-existing dust in the progenitor circumstellar medium (CSM). [ABRIDGED] Possible origins for the NIR emission are considered. Significant radioactive heating of ejecta dust is ruled out, as is shock/X-ray-precursor heating of CSM dust. More plausible sources are (a) an IR-echo from CSM dust driven by the UV/optical peak luminosity, and (b) emission from newly-condensed dust which formed within a cool, dense shell produced by the ejecta shock/CSM interaction. We argue that the evidence favours the condensing dust hypothesis, although an IR-echo is not ruled out. Within the condensing-dust scenario, the IR luminosity indicates the presence of at least 0.001 solar masses of dust in the ejecta, and probably considerably more. Finally, we show that the late-time intrinsic (K-L') evolution of type II supernovae may provide a useful tool for determining the presence or absence of a massive CSM around their progenitor stars.Comment: 23 pages, 15 figures, to be published in MNRA

Analysis of role-play in medical communication training using a theatrical device the fourth wall

BACKGROUND: Communication training is a central part of medical education. The aim of this article is to explore the positions and didactic functions of the fourth wall in medical communication training, using a role-play model basically similar to a theatrical performance. METHOD: The empirical data stem from a communication training model demonstrated at an international workshop for medical teachers and course organizers. The model involves an actress playing a patient, students alternating in the role of the doctor, and a teacher who moderates. The workshop was videotaped and analyzed qualitatively. RESULTS: The analysis of the empirical material revealed three main locations of the fourth wall as it moved and changed qualities during the learning session: 1) A traditional theatre location, where the wall was transparent for the audience, but opaque for the participants in the fiction. 2) A "timeout/reflection" location, where the wall was doubly opaque, for the patient on the one side and the moderator, the doctor and the audience on the other side and 3) an "interviewing the character" location where the wall enclosed everybody in the room. All three locations may contribute to the learning process. CONCLUSION: The theatrical concept 'the fourth wall' may present an additional tool for new understanding of fiction based communication training. Increased understanding of such an activity may help medical teachers/course organizers in planning and evaluating communication training courses

Academic Performance and Behavioral Patterns

Identifying the factors that influence academic performance is an essential part of educational research. Previous studies have documented the importance of personality traits, class attendance, and social network structure. Because most of these analyses were based on a single behavioral aspect and/or small sample sizes, there is currently no quantification of the interplay of these factors. Here, we study the academic performance among a cohort of 538 undergraduate students forming a single, densely connected social network. Our work is based on data collected using smartphones, which the students used as their primary phones for two years. The availability of multi-channel data from a single population allows us to directly compare the explanatory power of individual and social characteristics. We find that the most informative indicators of performance are based on social ties and that network indicators result in better model performance than individual characteristics (including both personality and class attendance). We confirm earlier findings that class attendance is the most important predictor among individual characteristics. Finally, our results suggest the presence of strong homophily and/or peer effects among university students

Environmental Emission of Pharmaceuticals from Wastewater Treatment Plants in the USA

The residual drugs, drug bioconjugates, and their metabolites, mostly from human and veterinary usage, are routinely flushed down the drain, and enter wastewater treatment plants (WWTP). Increasing population, excessive use of allopathic medicine, continual introduction of novel drugs, and existing inefficient wastewater treatment processes result in the discharge of large volumes of pharmaceuticals and their metabolites from the WWTPs into the environment. The effluent from the WWTPs globally contaminate ~25% of rivers and the lakes. Pharmaceuticals in the environment, as contaminants of emerging concerns, behave as pseudo-persistent despite their relatively short environmental half-lives in the environment. Therefore, residual levels of pharmaceuticals in the environment not only pose a threat to the wildlife but also affect human health through contaminated food and drinking water. This chapter highlights WWTPs as point-sources of their environmental emissions and various effects on the aquatic and terrestrial ecosystem

Molecular excitation in the Interstellar Medium: recent advances in collisional, radiative and chemical processes

We review the different excitation processes in the interstellar mediumComment: Accepted in Chem. Re