382 research outputs found

    Detection of CI line emission from the detached CO shell of the AGB star R Sculptoris

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    Stars on the asymptotic giant branch (AGB) lose substantial amounts of matter, to the extent that they are important for the chemical evolution of, and dust production in, the universe. The mass loss is believed to increase gradually with age on the AGB, but it may also occur in the form of bursts, possibly related to the thermal pulsing phenomenon. Detached, geometrically thin, CO shells around carbon stars are good signposts of brief and intense mass ejection. We aim to put further constraints on the physical properties of detached CO shells around AGB stars. The photodissociation of CO and other carbon-bearing species in the shells leads to the possibility of detecting lines from neutral carbon. We have therefore searched for the CI(^3P_1-\,^3P_0) line at 492 GHz towards two carbon stars, S Sct and R Scl, with detached CO shells of different ages, about 8000 and 2300 years, respectively. The CI(^3P_1-\,^3P_0) line was detected towards R Scl. The line intensity is dominated by emission from the detached shell. The detection is at a level consistent with the neutral carbon coming from the full photodissociation of all species except CO, and with only limited photoionisation of carbon. The best fit to the observed 12^{12}CO and 13^{13}CO line intensities, assuming a homogeneous shell, is obtained for a shell mass of about 0.002 M⊙M_\odot, a temperature of about 100 K, and a CO abundance with respect to H2_2 of 10−3^{-3}. The estimated CI/CO abundance ratio is about 0.3 for the best-fit model. However, a number of arguments point in the direction of a clumpy medium, and a viable interpretation of the data within such a context is provided

    Strategic Investments in the Pulp and Paper Industry: A Count Data Regression Analysis

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    This paper analyses the effects of price and market size variables on the investment propensities in the pulp and paper industry. A panel of 15 European countries in the time period 1984 - 1997 is used in the regression analysis. We find the wages, the US/ECU exchange rate, the price of paper and the installed production capacity to be the main determinants of strategic investments in this industry. Our measure of market size have no - or only very small - effects.Lumpy investments; Prices; Market size; Agglomeration; Distance; Investment determinants

    Taking Biologics for Granted? Takings, Trade Secrets, and Off-Patent Biological Products

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    Biologics are complex medicines which are often genetically engineered, and which are sure to play an important role in curing some of humankind\u27s worst diseases. Not surprisingly, generic companies want a part of the biologic market. The FDA believes that it has the authority to approve off-patent versions of biologics that were originally regulated under the Food, Drug & Cosmetic Act, but in order to effectively do so the FDA would have to rely on findings based on data produced by the brand name companies. This iBrief examines whether the FDA\u27s reliance on previous findings would give rise to a valid claim under the Takings Clause of the U.S. Constitution. In the end, it concludes that the FDA\u27s proposed action likely would not constitute a taking

    Misinformation, Misrepresentation, and Misuse of Human Behavioral Genetics Research

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    Kaplan discusses the limitations of human behavioral genetics studies, highlighting the research limitations inherent in studying humans and the narrow policy and legal applicability of results arising from behavioral genetics studies

    Journal Staff

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    Background: Internet-based cognitive behavioral therapy (ICBT) is a form of guided self-help that has been found to be effective for addressing several problems. The target for this type of therapy is usually restricted to one specific disorder. Tailoring the treatment widens the scope of ICBT in that it can address comorbid conditions directly. Objectives: The working, or therapeutic, alliance has been found to predict outcome in studies of face-to-face therapy. The extent to which these findings apply to ICBT is largely unknown. We therefore decided to find out whether the working alliance could predict outcome in tailored ICBT for anxiety disorders. Methods: Data were obtained from the treatment group (n=27) in a randomized controlled trial aiming to test the effects of tailored ICBT for anxiety disorders. The forthcoming study was designed to test the hypothesis that the working alliance measured both pre-treatment and early in treatment (week 3) can predict treatment outcome as measured by the Clinical Outcomes in Routine Evaluation–Outcome Measure (CORE-OM) in a heterogeneous group of patients with anxiety disorders (n=27). Results: Working alliance measured at week 3 into the treatment correlated significantly with the residual gain scores on the primary outcome measure (r=-.47, P=.019, n=25), while expected working alliance pre-treatment did not (r=-.17, P=.42, n=27). Conclusions: These results raise questions about the importance of working alliance in ICBT treatments, and suggest that the working alliance could be important in ICBT.Funding Agencies|Swedish Council for Working Life and Social Research|2008-1145|</p

    APEX Millimeter Observations of Methanol Emission Toward High-Mass Star-Forming Cores

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    We present 247-GHz molecular line observations of methanol (CH3_3OH) toward sixteen massive star-forming regions, using the APEX telescope with an angular resolution of 25′′25''. The sample covers a range of evolutionary states, including warm molecular cores, hot molecular cores, and ultracompact HII regions. The hot cores, all of which include UC HII regions, show rich molecular line spectra, although the strength of different species and transitions varies from source to source. In contrast, the warm cores do not show significant molecular line emission. Multiple methanol transitions are detected toward nine of the hot cores; eight of these had enough transitions to use the rotation diagram method to estimate rotational temperatures and column densities. The temperatures lie in the range 104−-168 K and column densities from 3×10163\times10^{16} to 7×10187\times10^{18} cm−2^{-2}. Using the average methanol line parameters, we estimate virial masses, which fall in the range from 145 to 720 M⊙_\odot and proved to be significantly higher than the measured gas masses. We discuss possible scenarios to explain the chemical differences between hot cores and warm molecular cores. One of the observed methanol lines, 42−51A+4_{2}-5_{1}A^{+} at 247.228 GHz, is predicted to show class II maser emission, similar in intensity to previously reported J0−J−1EJ_0-J_{-1}E masers at 157 GHz. We did not find any clear evidence for maser emission among the observed sources; however, a weak maser in this line may exist in G345.01+1.79.Comment: Accepted for publication in The Astronomical Journa

    G345.45+1.50: An expanding ring-like structure with massive star formation

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    Ring-like structures in the ISM are commonly associated with high-mass stars. Kinematic studies of large structures in GMCs toward these ring-like structures may help us to understand how massive stars form. The origin and properties of the ring-like structure G345.45+1.50 is investigated through observations of the 13CO(3-2) line. The aim of the observations is to determine the kinematics in the region and to compare physical characteristics estimated from gas emission with those previously determined using dust continuum emission. The 13CO(3-2) line was mapped toward the whole ring using the APEX telescope. The ring is found to be expanding with a velocity of 1.0 km/s, containing a total mass of 6.9e3 Msun, which agrees well with that determined using 1.2 mm dust continuum emission. An expansion timescale of 3e6 yr and a total energy of 7e46 erg are estimated. The origin of the ring might have been a supernova explosion, since a 35.5 cm source, J165920-400424, is located at the center of the ring without an infrared counterpart. The ring is fragmented, and 104 clumps were identified with diameters of between 0.3 and 1.6 pc, masses of between 2.3 and 7.5e2 Msun, and densities of between 1.0e2 and 1.0e4 cm^-3. At least 18% of the clumps are forming stars, as is shown in infrared images. Assuming that the clumps can be modeled as Bonnor-Ebert spheres, 13 clumps are collapsing, and the rest of them are in hydrostatic equilibrium with an external pressure with a median value of 4e4 K cm^-3. In the region, the molecular outflow IRAS 16562-3959 is identified, with a velocity range of 38.4 km/s, total mass of 13 Msun, and kinematic energy of 7e45 erg. Finally, five filamentary structures were found at the edge of the ring with an average size of 3 pc, a width of 0.6 pc, a mass of 2e2 Msun, and a column density of 6e21 cm^-2

    First detection of methanol towards a post-AGB object, HD101584

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    The circumstellar environments of objects on the asymptotic giant branch and beyond are rich in molecular species. Nevertheless, methanol has never been detected in such an object, and is therefore often taken as a clear signpost for a young stellar object. However, we report the first detection of CH3OH in a post-AGB object, HD101584, using ALMA. Its emission, together with emissions from CO, SiO, SO, CS, and H2CO, comes from two extreme velocity spots on either side of the object where a high-velocity outflow appears to interact with the surrounding medium. We have derived molecular abundances, and propose that the detected molecular species are the effect of a post-shock chemistry where circumstellar grains play a role. We further provide evidence that HD101584 was a low-mass, M-type AGB star

    Decreased incidence of postoperative stroke following off-pump coronary artery bypass: Reply

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