Computer simulations of seasonal outbreak and diurnal vertical migration of cyanobacteria

Algal blooms caused by cyanobacteria are characterized by two features with different time scales: one is seasonal outbreak and collapse of a bloom and the other is diurnal vertical migration. Our two-component mathematical model can simulate both phenomena, in which the state variables are nutrients and cyanobacteria. The model is a set of one-dimensional reaction-advection-diffusion equations, and temporal changes of these two variables are regulated by the following five factors: (1) annual variation of light intensity, (2) diurnal variation of light intensity, (3) annual variation of water temperature, (4) thermal stratification within a water column and (5) the buoyancy regulation mechanism. The seasonal change of cyanobacteria biomass is mainly controlled by factors, (1), (3) and (4), among which annual variations of light intensity and water temperature directly affect the maximum growth rate of cyanobacteria. The latter also contributes to formation of the thermocline during the summer season. Thermal stratification causes a reduction in vertical diffusion and largely prevents mixing of both nutrients and cyanobacteria between the epilimnion and the hypolimnion. Meanwhile, the other two factors, (2) and (5), play a significant role in diurnal vertical migration of cyanobacteria. A key mechanism of vertical migration is buoyancy regulation due to gas-vesicle synthesis and ballast formation, by which a quick reversal between floating and sinking becomes possible within a water column. The mechanism of bloom formation controlled by these five factors is integrated into the one-dimensional model consisting of two reaction-advection-diffusion equations.

Weakly nonlinear vertical dust grain oscillations in dusty plasma crystals in the presence of a magnetic field

The weakly nonlinear regime of transverse paramagnetic dust grain oscillations in dusty (complex) plasma crystals is discussed. The nonlinearity, which is related to the sheath electric/magnetic field(s) and to the intergrain (electrostatic/magnetic dipole) interactions, is shown to lead to the generation of phase harmonics and, in the case of propagating transverse dust-lattice modes, to the modulational instability of the carrier wave due to self-interaction. The stability profile depends explicitly on the form of the electric and magnetic fields in the plasma sheath. The long term evolution of the modulated wave packet, which is described by a nonlinear Schrodinger-type equation, may lead to propagating localized envelope structures whose exact forms are presented and discussed. Explicit suggestions for experimental investigations are put forward. (C) 2004 American Institute of Physics.

Discrete breather modes associated with vertical dust grain oscillations in dusty plasma crystals

Accounting for the lattice discreteness and the sheath electric field nonlinearity in dusty plasma crystals, it is demonstrated that highly localized structures (discrete breathers) involving vertical (transverse, off-plane) oscillations of charged dust grains may exist in a dust lattice. These structures correspond to either extremely localized bright breather excitations (pulses) or dark excitations composed of dips/voids. Explicit criteria for selecting different breather modes are presented. (C) 2005 American Institute of Physics.

Understanding Accountability in Social Enterprise Organisations: A Framework

Purpose: Social enterprise organisations (SEOs) operate across the boundaries of the public, private and not‐for‐profit (NFP) sectors in delivering public services and competing for resources and legitimacy. While there is a rich literature on accountability in the private and public sectors, together with the wider NFP sector, SEOs have received comparatively little attention and remain a relatively under‐researched organisational form. Drawing on accountability, legitimacy and user‐needs theories, the purpose of this paper is to develop a practical framework which can be used to explore how accountability within SEOs is constructed and discharged.

Design/methodology/approach: This paper draws on user‐needs, accountability, legitimacy and impression management theories expounded in relation to the private, public and NFP sectors.

Findings: A framework to better understand how accountability can be discharged by SEOs is developed and discussed.

Research limitations/implications: While a framework for better understanding SEO accountability is presented, it is not empirically tested. However, the framework has the potential to facilitate a deeper appreciation of the theory and practice of accountability within SEOs and, notwithstanding the inherent difficulties in measuring and managing accountability, could be used to stimulate practitioner involvement.

Practical implications
– As little is known about the current extent of SEO information disclosure or accountability relationships, the framework could be used to assess the discharge of accountability by SEOs, with the findings informing future developments. This should provide useful insights into internal processes and organisational views on accountability bases and mechanisms and can then be used to inform the debate on how SEOs can best discharge their duty to account.

Social implications
– Understanding the nature of SEO accountability reporting has important implications for those involved in advancing the SEO agenda. At a time of public sector cutbacks, and with the government searching for new and more effective ways of delivering services, the role of SEOs in this process is likely to receive greater attention and scrutiny.

Originality/value
– SEOs have grown extensively in size and prominence in recent years and policymakers have come to embrace the role that they play in societal development. This paper responds to a gap in the theoretical literature and contributes to the debate by developing a framework which can be empirically tested. Moreover, it can be used to prompt practitioner involvement and facilitate a better understanding of the complex issues surrounding accounting and accountability in this under‐researched 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.

Crucial silences: When Accountability Met PFI and Finance Capital

During recent years, a wide spectrum of research has questioned whether public services/infrastructure procurement through private finance, as exemplified by the UK Private Finance Initiative (PFI), meets minimum standards of democratic accountability. While broadly agreeing with some of these arguments, this paper suggests that this debate is flawed on two grounds. Firstly, PFI is not about effective procurement, or even about a pragmatic choice of procurement mechanisms which can potentially compromise public involvement and input; rather it is about a process where the state creates new profit opportunities at a time when the international financial system is increasingly lacking in safe investment opportunities. Secondly, because of its primary function as investment opportunity, PFI, by its very nature, prioritises the risk-return criteria of private finance over the needs of the public sector client and its stakeholders. Using two case studies of recent PFI projects, the paper illustrates some of the mechanisms through which finance capital exercises control over the PFI procurement process. The paper concludes that recent proposals aimed at “reforming” or “democratising” PFI fail to recognise the objective constraints which this type of state-finance capital nexus imposes on political process.

Accountability and Value for Money: A Framework for Exploring the Relationship in Private Finance Initiative Contracts

There is an implicit assumption in the UK Treasury’s publications on public-private partnerships (PPP) – also more commonly known in the United Kingdom as private finance initiative (PFI) - that accountability and value for money (VFM) are related concepts. While recent academic studies on PPP/PFI (from now on as PFI) have focused on VFM, there is a notable absence of studies exploring the ‘presumed’ relationships between accountability and VFM. Drawing on Dubnick’s (Dubnick and Romzek, 1991, 1993; Dubnick, 1996, 1998, 2003, 2005; Dubnick and Justice, 2002) framework for accountability and PFI literature, we develop a research framework for exploring potential relationships between accountability and VFM in PFI projects by proposing alternative accountability cultures, processes and mechanisms for PFI. The PFI accountability model is then exposed to four criteria - warrantability, tractability, measurability and feasibility. Our preliminary interviews provide us guidance in identifying some of the cultures, processes and mechanisms indicated in our model which should enable future researchers to test not only the UK Government’s claimed relationships between accountability and VFM using more specific PFI empirical data, but also a potential relationship between accountability and performance in general.

Contesting public accountability: A dialogical exploration of accountability and social housing

This paper analyses the interaction between neoliberal inspired reforms of public services and the mechanisms for achieving public accountability. Where once accountability was exercised through the ballot box, now in the neoliberal age managerial and market based forms of accountability predominate. The analysis identifies resistance from civil society campaigns to the neoliberal restructuring of public services which leads to public accountability (PA) becoming a contested arena. To develop this analysis a re-theorisation of PA, as a relationship where civil society seeks to control the state, is explored in the context of social housing in England over the past thirty years. Central to this analysis is a dialogical analysis of key documents from a social housing regulator and civil society campaign. The analysis shows that the current PA practices are an outcome of both reforms from the government and resistance from civil society (in the shape of tenants’ campaigns). The outcome of which is to tell the story of the changes in PA (and accountability) centring on an analysis of discourse. Thus, the paper moves towards answering the question – what has happened to PA during the neoliberal age?

Prospective study of workplace social capital and depression: are vertical and horizontal components equally important?

Background Recent studies have emphasised the multidimensional nature of the social capital concept, but it is not known whether the health effects of social capital vary by dimension. The objective of this study was to examine the vertical component (ie, respectful and trusting relationships across power differentials at work) and the horizontal component of workplace social capital (trust and reciprocity between employees at the same hierarchical level) as risk factors for subsequent depression.

Towards Charity Accountability: Narrowing the gap between provision and needs?

Although charities currently play a rich and varied role in modern society, their continued success is dependent upon the public's trust. With respect to charity accountability, two key questions emerge: to whom is a charity accountable; and what form should that account take? Despite the widespread acceptance that charities should discharge accountability, there is limited knowledge of the relative importance of different stakeholder groups and whether the information currently being disclosed meets their needs. Using extensive document analysis and a survey of stakeholders, this research explores these issues in the context of the top 100 UK fundraising charities. Furthermore, it compares the results with much earlier research to identify changes over time.