2,733 research outputs found
CO+ in M 82: A Consequence of Irradiation by X-rays
Based on its strong CO+ emission it is argued that the M 82 star-burst galaxy
is exposed to a combination of FUV and X-ray radiation. The latter is likely to
be the result of the star-burst superwind, which leads to diffuse thermal
emission at ~0.7 keV, and a compact hard, 2-10 keV, source (but not an AGN).
Although a photon-dominated region (FUV) component is clearly present in the
nucleus of M 82, and capable of forming CO+, only X-ray irradiated gas of
density 10^3-10^5 cm^-3 can reproduce the large, ~(1-4)x10^13 cm^-2, columns of
CO+ that are observed toward the proto-typical star-burst M 82. The total X-ray
luminosity produced by M 82 is weak, ~10^41 erg s^-1, but this is sufficient to
drive the formation of CO+.Comment: added discussion on more recent X-ray observation
Window to the West : Memories of watching Finnish television in Estonia during the Soviet period
This study is concerned with the memories that Estonians have of watching Finnish television during the last decades of the Soviet occupation. We will look at the practices of watching Finnish television in Soviet Estonia and the meanings attributed to it. Finnish television took North-Estonians into a colourful world of consumption and entertainment, while educating them about Western values and encouraging them to dream of a better future. We identify four ways that North-Estonians remember Finnish television (and its programmes): as an event, as a means of distinction, as a window to a world of affluence, and as a tool of democratic education.Peer reviewe
The first year of the Academia Gustaviana print shop as seen through the history of paper
Watermarks and paper evidence are useful tools for researching manuscripts as well as printed books on paper, and not only for dating and identifying authenticity, but for studying the history of documents and printed books as material objects themselves. The present paper is based on the publications printed in Tartu in 1632, the first year of operation of the Swedish-era University of Tartu print shop, and the paper used in them. The purpose is to study the watermarks gathered from all survived copies of publications deposited in Estonia, to discuss the possible origins of the paper and the principles for its acquisition and use, and to draw some conclusions concerning general conditions of printing and the printer’ personal contacts and preferences during the early days of the print shop.
Keywords: 17th century, Livonia, University of Tartu, printing history, handmade rag paper, watermark
Methanogenic \u3cem\u3eArchaea\u3c/em\u3e and human periodontal disease
Archaea have been isolated from the human colon, vagina, and oral cavity, but have not been established as causes of human disease. In this study, we reveal a relationship between the severity of periodontal disease and the relative abundance of archaeal small subunit ribosomal RNA genes (SSU rDNA) in the subgingival crevice by using quantitative PCR. Furthermore, the relative abundance of archaeal small subunit rDNA decreased at treated sites in association with clinical improvement. Archaea were harbored by 36% of periodontitis patients and were restricted to subgingival sites with periodontal disease. The presence of archaeal cells at these sites was confirmed by fluorescent in situ hybridization. The archaeal community at diseased sites was dominated by a Methanobrevibacter oralis-like phylotype and a distinct Methanobrevibacter subpopulation related to archaea that inhabit the gut of numerous animals. We hypothesize that methanogens participate in syntrophic relationships in the subgingival crevice that promote colonization by secondary fermenters during periodontitis. Because they are potential alternative syntrophic partners, our finding of larger Treponema populations sites without archaea provides further support for this hypothesis
Gender Differences in Response to a School-Based Mindfulness Training Intervention for Early Adolescents
Mindfulness training has been used to improve emotional wellbeing in early adolescents. However, little is known about treatment outcome moderators, or individual differences that may differentially impact responses to treatment. The current study focused on gender as a potential moderator for affective outcomes in response to school-based mindfulness training. Sixth grade students (N = 100) were randomly assigned to either the six weeks of mindfulness meditation or the active control group as part of a history class curriculum. Participants in the mindfulness meditation group completed short mindfulness meditation sessions four to five times per week, in addition to didactic instruction (Asian history). The control group received matched experiential activity in addition to didactic instruction (African history) from the same teacher with no meditation component. Self-reported measures of emotional wellbeing/affect, mindfulness, and self-compassion were obtained at pre and post intervention. Meditators reported greater improvement in emotional wellbeing compared to those in the control group. Importantly, gender differences were detected, such that female meditators reported greater increases in positive affect compared to females in the control group, whereas male meditators and control males displayed equivalent gains. Uniquely among females but not males, increases in self-reported self-compassion were associated with improvements in affect. These findings support the efficacy of school-based mindfulness interventions, and interventions tailored to accommodate distinct developmental needs of female and male adolescents
HCN to HCO^+ Millimeter Line Diagnostics of AGN Molecular Torus I : Radiative Transfer Modeling
We explore millimeter line diagnostics of an obscuring molecular torus
modeled by a hydrodynamic simulation with three-dimensional nonLTE radiative
transfer calculations. Based on the results of high-resolution hydrodynamic
simulation of the molecular torus around an AGN, we calculate intensities of
HCN and HCO^{+} rotational lines as two representative high density tracers.
The three-dimensional radiative transfer calculations shed light on a
complicated excitation state in the inhomogeneous torus, even though a
spatially uniform chemical structure is assumed. Our results suggest that HCN
must be much more abundant than HCO^{+} in order to obtain a high ratio
() observed in some of the nearby galaxies. There is a
remarkable dispersion in the relation between integrated intensity and column
density, indicative of possible shortcomings of HCN(1-0) and HCO^{+}(1-0) lines
as high density tracers. The internal structures of the inhomogeneous molecular
torus down to subparsec scale in external galaxies will be revealed by the
forthcoming Atacama Large Millimeter/submillimeter Array (ALMA). The
three-dimensional radiative transfer calculations of molecular lines with
high-resolution hydrodynamic simulation prove to be a powerful tool to provide
a physical basis for molecular line diagnostics of the central regions of
external galaxies.Comment: 29 pages, 13 figures, Accepted for publication in ApJ, For high
resolution figures see http://alma.mtk.nao.ac.jp/~masako/MS72533v2.pd
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
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