Numerical modeling of the disruption of Comet D/1993 F2 Shoemaker-Levy 9 representing the progenitor by a gravitationally bound assemblage of randomly shaped polyhedra

We advance the modeling of rubble-pile solid bodies by re-examining the tidal breakup of comet Shoemaker-Levy 9, an event that occurred during a 1.33 Jupiter radii encounter with that planet in July 1992. Tidal disruption of the comet nucleus led to a chain of sub-nuclei about 100-1000 m in diameter; these went on to collide with the planet two years later (Chodas & Yeomans 1996). They were intensively studied prior to and during the collisions, making SL9 the best natural benchmark for physical models of small body disruption. For the first time in the study of this event, we use numerical codes treating rubble-piles as collections of polyhedra (Korycansky & Asphaug 2009). This introduces forces of dilatation and friction, and inelastic response. As in our previous studies (Asphaug & Benz 1994,1996) we conclude that the progenitor must have been a rubble-pile, and we obtain approximately the same pre-breakup diameter (about 1.5 km) in our best fits to the data. We find that the inclusion of realistic fragment shapes leads to grain locking and dilatancy, so that even in the absence of friction or other dissipation we find that disruption is overall more difficult than in our spheres-based simulations. We constrain the comet's bulk density at about 300-400 kg/m^3, half that of our spheres-based predictions and consistent with recent estimates derived from spacecraft observations.Comment: Submitted to The Astrophysical Journal (7/16/12) added Acknowledgments (8/29/12) accepted, peer reviewed versio

What do We Know About Entrepreneurial Finance and its Relationship with Growth?

This article explores what we do (and do not) know about entrepreneurial finance and its relationship with growth. Broadly, there is a need for research to go beyond traditional supply side/market failure issues to better understand the role of entrepreneurial cognition, objectives, ownership types and firm life-cycle stages in financing/investment decisions. We show that little is known about the pivotal relationship between access to external finance and growth due to limitations in current approaches to testing financial constraints. Instead, we propose that the relationship between funding gaps and business performance as a direct and nuanced approach to identifying financial constraints in different entrepreneurial finance markets requires scrutiny. There is also a necessity for research to disentangle cognitive from financial constraints and to better understand the role of financiers in enabling growth. In particular, there is a need to explore the relationship between non-bank sources of finance and growth, shorn of inherent survival and selection bias. We outline an agenda for future research to address gaps in our understanding

Public sector commissioning and the third sector: Old wine in new bottles?

Public sector commissioning has risen rapidly to prominence as the central mechanism for the ‘purchase’ of services in an increasingly mixed economy of public services in the UK and this has wide-ranging consequences for non-state actors including those in the third sector. Academic consideration of commissioning has been rather fragmented, concerned with particular service fields or sectors. This paper provides an overview, with a focus on the relationship between the state and the third sector. The paper begins by questioning whether commissioning is really ‘new’ or a continuation of exist- ing trends around procurement and contracting and whether it constitutes a genuinely transformative relationship between the state and third sector. It considers some core debates about the likely impact of commissioning on the third sector and its relationship with the state. In doing so, the paper advances two main arguments: that commissioning remains highly fragmented in policy and practice, between different localities and scales of government; and that there is a tension within commissioning policy between the ‘rhetoric’ of the ‘full cycle’ approach based on needs assessment and planning, and what appears to be an emerging reality of resource-constrained, large-scale and Payment by Results-based contracting. These raise real concerns for organizational and service quality outcomes

A study of young peoples' attitudes to opportunistic Chlamydia testing in UK general practice

<p>Abstract</p> <p>Objective</p> <p>The objective of this study was to assess young people's perceptions of being offered a chlamydia screening test in United Kingdom (UK) general practice.</p> <p>Methods</p> <p>This is qualitative study that uses focus groups and individual interviews with young adults (age 16 – 18) to assess their views.</p> <p>Results</p> <p>These young adults were a difficult group to gain access to. Two focus groups, one in a school, the other in a general practice (family practice), and 2 individual interviews were undertaken (total sample 18). Respondents were unfamiliar with Chlamydia, but broadly aware of sexually transmitted infections. General practice (family practice) was perceived as an acceptable place to deliver opportunistic screening, but participants felt that tests should not be initiated by GP receptionists. Novel delivery routes such as schools and "Pub"/Bar dispensing machines were discussed. Issues around stigma and confidentiality were also raised.</p> <p>Conclusion</p> <p>Opportunistic Chlamydia screening in UK general practice (family practic seems acceptable to young adults. While this is a difficult group to gain access to for research, attempts need to made to ensure acceptability to users of this programme.</p

The geographies of access to enterprise finance: the case of the West Midlands, UK

The geographies of access to enterprise finance: the case of the West Midlands, UK, Regional Studies. Whilst there is a long history of credit rationing to small and medium-sized enterprises (SMEs) in the UK, the financial crisis has seen banks retreat further from lending to viable SMEs due to a reassessment of risk and lack of available capital. In so doing, the credit crunch is thought to be creating new geographies of financial exclusion. This paper explores the financial inclusion of enterprise through community development finance institutions (CDFIs) which provide loan finance to firms at the commercial margins in the West Midlands, UK. The paper concludes that CDFIs could partially address the financial exclusion of enterprise as an additional, alternative source of finance to that of mainstream banks

Theorising lifestyle drift in health promotion: explaining community and voluntary sector engagement practices in disadvantaged areas

The past two decades have seen an increasing role for the UK community and voluntary sector (CVS) in health promotion in disadvantaged areas, largely based on assumptions on the part of funders that CVS providers are better able to engage ‘hard-to-reach’ population groups in services than statutory providers. However, there is limited empirical research exploring CVS provider practices in this field. Using ethnographic data, this paper examines the experiences of a network of CVS providers seeking to engage residents in health-promoting community services in a disadvantaged region in the North of England. The paper shows how CVS providers engaged in apparently contradictory practices, fluctuating between an empathically informed response to complex resident circumstances and (in the context of meeting externally set targets) behavioural lifestyle approaches to health promotion. Drawing on concepts from figurational sociology, the paper explains how lifestyle drift occurs in health promotion as a result of the complex web of relations (with funders, commissioners and residents) in which CVS providers are embedded. Despite the fact that research has revealed the impact of targets on the work of the CVS before, this paper demonstrates more specifically the way in which monitoring processes within CVS contracts can draw providers into the neoliberal lifestyle discourse so prevalent in health promotion

Establishing a new UK finance escalator for innovative SMEs: the roles of the Enterprise Capital Funds and Angel Co-investment Fund

This paper examines UK public policy addressing the seed and early stage equity finance gap since the Global Financial Crisis (GFC). Drawing on lessons learned from recent studies of UK and international government equity schemes, two contemporary models of government backed equity finance are examined. The focus is on the Enterprise Capital Funds (ECFs) and the Angel Co-investment Fund (ACF), the UK government’s main schemes operating in the sub-£2m equity finance gap to address the capital requirements for developing the UK’s young, potential high growth businesses. The paper highlights the shortcomings of traditional interim fund performance analysis and presents current demand and supply side evidence that establishes that these schemes are making attributable impacts on their portfolio businesses and the wider UK economy. It also demonstrates that they are playing important roles in the establishment of a new post GFC UK finance escalator. However, whilst these schemes were found to be currently complementary and effective, their future roles within the UK’s evolving post GFC seed and early stage equity markets are also considered. Key Words: Government Equity Schemes, Venture Capital, Potential High Growth SME

Social enterprises with environmental objectives: saving traditional orchards in England and Germany

Social enterprises (SE) re-invest their profits towards a social mission. They have proliferated as post-industrial economies try to meet social need with limited state funding. Scholarship has expanded accordingly, although SEs with primarily environmental objectives have been neglected. This article examines how SEs, in regions noted for wildlife-rich orchards, fund nature conservation by marketing juice and/or cider, thereby attempting to revive economic possibilities for this traditional land use. A common thread between the SEs is their initiation by conservation organisations, and it is possible to group them within models of market intervention. Three models in particular are examined that reveal different approaches and success in orchard conservation. SE scholarship is marked by a wealth of case studies, and to avoid simply adding to this richness, the paper revisits Jen Beckert’s ideas on the social order of markets. His theory that actors strive for stability through forms of co-ordination in dynamic market ‘fields’ is applied to SEs aiming to produce positive conservation outcomes – or environmental order – from their market interventions. Within limits, social order advances understanding of environmental SE by identifying the multiple challenges they juggle, and revealing the environmental outcomes of SE engagement in markets