An investigation of Fe XV emission lines in solar flare spectra

Previously, large discrepancies have been found between theory and observation for Fe XV emission line ratios in solar flare spectra covering the 224-327 angstrom wavelength range, obtained by the Naval Research Laboratory's S082A instrument on board Skylab. These discrepancies have been attributed to either errors in the adopted atomic data or the presence of additional atomic processes not included in the modelling, such as fluorescence. However our analysis of these plus other S082A flare observations (the latter containing Fe XV transitions between 321-482 angstrom), performed using the most recent Fe XV atomic physics calculations in conjunction with a chianti synthetic flare spectrum, indicate that blending of the lines is primarily responsible for the discrepancies. As a result, most Fe XV lines cannot be employed as electron density diagnostics for solar flares, at least at the spectral resolution of S082A and similar instruments (i.e.similar to 0.1 angstrom). An exception is the intensity ratio I(3s3p P-3(2)-3p(2) P-3(1))/I(3s3p P-3(2)-3p(2) D-1(2))=I(321.8 angstrom)/I(327.0 angstrom), which appears to provide good estimates of the electron density at this spectral resolution.

Governance and charities: An exploration of key themes and the development of a research agenda

The concept of governance has been widely discussed in both the business and non-business sectors. The debate has also been entered into within the charity sector, which comprises over 169,000 organizations in the UK. The UK-based Charity Commission, which describes itself as existing to ‘promote sound governance and accountability’, has taken a lead in this debate by promoting greater regulation and producing numerous recommendations with regard to the proper governance of charitable organizations. However, the concept of what is meant by governance is unclear and a myriad of ideas are placed under the umbrella of ‘good governance’. This paper explores the major themes that form the basis of much of this discussion, examining both the theoretical underpinnings and empirical investigations relating to this area (looking from the perspective of the key stakeholders in the charity sector). Based on an analysis of the extant literature, this paper presents a broad definition of governance with respect to charities and outlines a future research agenda for those interested in adding to knowledge in this area.

Discharging not-for-profit accountability: UK charities and public discourse

Purpose: This paper aims to examine the accountability practices of large United Kingdom (UK) charities through public discourse.
Design/methodology/approach: Based on the ethical model of stakeholder theory, the paper develops a framework for classifying not-for-profit (NFP) accountability and analyzes the content of the annual reports and annual reviews of a sample of large UK charities using this framework.
Findings: The results suggest that contrary to the ethical model of stakeholder theory, the sample charities’ accountability practices are motivated by a desire to legitimize their activities and present their organizations’ activities in a positive light. These results contradict the raison d’eˆ tre of NFP organizations (NFPOs) and the values that they espouse. Research limitations/implications: Understanding the nature of accountability reporting in NFPOs has important implications for preparers and policy makers involved in furthering the NFP agenda. New research needs to examine shifts in accountability practices over time and assess the impact of the recent self-regulation developed to enhance sector accountability.
Originality/value: This paper contributes to the NFP accountability literature by: first, developing a framework of NFP accountability through public discourse using the ethical model of stakeholder theory; and second, advancing the understanding of the accountability practices of large UK charities.

Energy levels, radiative rates and electron impact excitation rates for transitions in Si XII, Si XIII and Si XIV

In this paper, we report calculations of energy levels, radiative rates and electron impact excitation rates for transitions in Li-like Si XII, He-like Si XIII and H-like Si XIV. The grasp (general-purpose relativistic atomic structure package) is adopted for calculating energy levels and radiative rates, while for determining the collision strengths and subsequently the excitation rates, the Dirac atomic R-matrix code (darc) is used. Oscillator strengths, radiative rates and line strengths are reported for all E1, E2, M1 and M2 transitions among the lowest 24 levels of Si XII, 49 levels of Si XIII and 25 levels of Si XIV, belonging to the n≤5 configurations. Collision strengths have been averaged over a Maxwellian electron velocity distribution and the effective collision strengths so obtained are reported over a wide temperature range below 107 K. Comparisons have been made with similar data obtained from the flexible atomic code (fac) to highlight the importance of resonances, included in calculations from darc, in the determination of effective collision strengths. Discrepancies between the collision strengths from darc and fac, particularly for weak transitions and at low energies, are also discussed. Additionally, lifetimes are listed for all calculated levels of the above three ions, although no measurements are available with which to compare.