7,558 research outputs found
CN excitation and electron densities in diffuse molecular clouds
Utilising previous work by the authors on the spin-coupled rotational
cross-sections for electron-CN collisions, data for the associated rate
coefficients is presented. Data on rotational, fine-structure and
hyperfine-structure transition involving rotational levels up to =20 are
computed for temperatures in the range 10 -- 1000~K. Rates are calculated by
combining Born-corrected R-matrix calculations with the infinite-order-sudden
(IOS) approximation. The dominant hyperfine transitions are those with . For dipole-allowed transitions, electron-impact rates
are shown to exceed those for excitation of CN by para-H() by five
orders of magnitude. The role of electron collisions in the excitation of CN in
diffuse clouds, where local excitation competes with the cosmic microwave
background (CMB) photons, is considered. Radiative transfer calculations are
performed and the results compared to observations. These comparisons suggest
that electron density lies in the range ~cm for
typical physical conditions present in diffuse clouds.Comment: 6 pages, 8 figures, accepted 14/08/201
Socio-Economic Evaluation of the Potential for Australian Tree Species in the Philippines
Crop Production/Industries,
Empirical investigation of investment behaviour in Australia's pastoral region
Optimal intertemporal investment behaviour ofAustralian pastoralists is modelled using panel data for the period 1979–1993.Results indicate that quasi-fixity of inputs of labour, capital, sheep numbers and cattle numbers is characteristic of production in the pastoral region. It takes about two years for labour, four years for capital and a little over two years for both sheep numbers and cattle numbers to adjust towards long-run optimal levels. Results also indicate that, after accounting for adjustment costs, own-price product supply and input demand responses are inelastic in both the short and long run.adjustment costs, pastoralism, supply response, Agribusiness,
The relationship between EUV dimming and coronal mass ejections
Aims.
There have been many studies of extreme-ultraviolet (EUV) dimming in association with coronal mass ejection (CME) onsets. However, there has never been a thorough statistical study of this association, covering appropriate temperature ranges. Thus, we make use of a large campaign database utilising the Coronal Diagnostic Spectrometer (CDS) and the Large Angle and Spectrometric COronagraph (LASCO) both on the SOlar and Heliospheric Observatory (SOHO) to associate dimming events detected at 1 and 2 million K with CME activity. The aim is to confirm whether the dimming-CME association is real or not. This in turn will confirm whether special attention should be paid to the EUV dimming in the pre-eruption and eruption periods to study the CME onset process itself.
Methods.
The CDS CME onset campaign data for Mg IX and FE XVI observations on the solar limb are used to compare to LASCO event lists over a period from 1998 to 2005. Dimming events are identified and the physical extent explored, whilst comparing the events to overlying CME activity.
Results.
For the identified dimming regions we have shown strong associations with CME onsets, with up to 55% of the dimming events being associated with CME activity. This is compared to the random case where up to 47% of the dimming regions are expected to be associated with CMEs. We have also shown that up to 84% of CMEs associated with our data can be tracked back to dimming regions. This compares to a random case of up to 58%.
Conclusions.
These results confirm the CME-EUV dimming association, using a statistical analysis for the first time. We discuss the repercussions for the study of CME onsets, i.e. analysis of the dimming regions and the periods up to such dimming may be key to understanding the pre-CME onset plasma processes. The results stress that one emission line may not be sufficient for associating dimming regions with CMEs
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Viral Membrane Fusion
Infection by viruses having lipid-bilayer envelopes proceeds through fusion of the viral membrane with a membrane of the target cell. Viral ‘fusion proteins’ facilitate this process. They vary greatly in structure, but all seem to have a common mechanism of action, in which a ligand-triggered, largescale conformational change in the fusion protein is coupled to apposition and merger of the two bilayers. We describe three examples—the influenza virus hemagglutinin, the flavivirus E protein and the vesicular stomatitis virus G protein—in some detail, to illustrate the ways in which different structures have evolved to implement this common mechanism. Fusion inhibitors can be effective antiviral agents.Chemistry and Chemical BiologyMolecular and Cellular Biolog
Themes and Patterns in Horace, Odes 2
This paper considers some formal elements of the second book of Horace’s Odes: the number, metre and length of poems, the architecture of the book and of some poems, the diversity of addressees, and the book’s relationship to some other contemporary literary texts
David Griffiths, Jane Harrison and Michael Athanson, Beside the Ocean: Coastal Landscapes at the Bay of Skaill, Marwick and Birsay Bay, Orkney: Archaeological Research 2003–2018
Beside the Ocean: Coastal Landscapes at the Bay of Skaill, Marwick and
Birsay Bay, Orkney: Archaeological Research 2003–2018
By David Griffiths, Jane Harrison and Michael Athanson. Oxford, Oxbow Books,
2019. Hardback. xxviii, 346 pp. ISBN 9781789250961. £45.00. (Digital Edition
ISBN 9781789250978)
A Model for Identifying, Developing, and Installing Elders in the Church: The Path Family Church has Taken
The problem is that Family Church does not identify, develop, and install their potential elders well. This intervention research project addressed this problem by establishing prerequisites for elder identification, a seven-week elder training workbook, and guidelines for installation after the research project. Current elders at Family Church completed a questionnaire, participated in case studies, and evaluated their intervention project in a focus group to establish an effective method of identifying, developing, and installing potential elders. This intervention research project produced a list of prerequisites for identifying potential elders, a seven-week elder training manual, and clear guidelines for ordaining elders at Family Church. This intervention also created a plan for one-on-one discipling relationships between current elders and potential elders for potential elder training, brought unity to the current elders, and reinforced the current elder\u27s understanding of eldership
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