598 research outputs found
Connection between the Largest Lyapunov Exponent, Density Fluctuation and Multifragmentation in Excited Nuclear Systems
Within a quantum molecular dynamics model we calculate the largest Lyapunov
exponent (LLE), density fluctuation and mass distribution of fragments for a
series of nuclear systems at different initial temperatures. It is found that
the peaks at the temperature ("critical temperature") where the density
fluctuation reaches a maximal value and the mass distribution of fragments is
best fitted by the Fisher's power law from which the critical exponents for
mass and charge distribution are obtained. The time-dependent behavior of the
LLE and density fluctuation is studied. We find that the time scale of the
density fluctuation is much longer than the inverse LLE, which indicates that
the chaotic motion can be well developed during the process of fragment
formation. The finite-size effect on "critical temperature" for nuclear systems
ranging from Calcium to superheavy nuclei is also studied.Comment: 18 pages, 8 figures Submited to Phys. Rev.
The role of hypothecation in financing transit: lessons from the UK
Two hypothecated charges to fund local public transport have recently passed
onto the statute books in the UK. The first is road user charging, with the London and
Durham the first to be implemented and the second is a workplace parking levy.
The use of such local hypothecated (or âearmarkedâ) mechanisms is not new.
Indeed a variety of such charges, local taxes and levies have been in use for decades
to fund public transport and (less frequently) as a tool for transport demand
management in the USA, Germany, Austria, Portugal, Scandinavia, India and
Singapore. In the general debate around the two new hypothecated charges in the UK,
this international experience has been largely neglected. The aim of this paper is to
detail a related and equally neglected area namely the local hypothecation of charges
to fund public transport improvements within Britain.
Under existing legislation it has been possible for some local authorities to
dedicate revenue streams from sources such as parking charges and planning gain to
develop and improve public transport services. There is also significant experience of
dedicated revenue streams in the private sector, for example at airports.
The paper details examples of the British experience of hypothecation and will
consider their lessons for the new and more radical measures that are now being
considered
Home sampling for sexually transmitted infections and HIV in men who have sex with men: A prospective observational study
To determine uptake of home sampling kit (HSK) for STI/HIV compared to clinic-based testing, whether the availability of HSK would increase STI testing rates amongst HIV infected MSM, and those attending a community-based HIV testing clinic compared to historical control. Prospective observational study in three facilities providing STI/HIV testing services in Brighton, UK was conducted. Adult MSM attending/contacting a GUM clinic requesting an STI screen (group 1), HIV infectedMSM attending routine outpatient clinic (group 2), and MSM attending a community-based rapid HIV testing service (group 3) were eligible. Participants were required to have no symptomatology consistent with STI and known to be immune to hepatitis A and B (group 1). Eligiblemen were offered a HSK to obtain self-collected specimens as an alternative to routine testing. HSK uptake compared to conventional clinicbased STI/HIV testing in group 1, increase in STI testing rates due to availability of HSK compared to historical controls in group 2 and 3, and HSK return rates in all settings were calculated. Among the 128 eligible men in group 1, HSK acceptance was higher (62.5% (95%CI: 53.5-70.9)) compared to GUM clinic-based testing (37.5% (95% CI: 29.1-46.5)), (p = 0.0004). Two thirds of eligibleMSM offered an HSK in all three groups accepted it, but HSK return rates varied (highest in group 1, 77.5%, lowest in group 3, 16%). HSK for HIV testing was acceptable to 81%of men in group 1. Compared to historical controls, availability of HSK increased the proportion ofMSM testing for STIs in group 2 but not in group 3. HSK for STI/ HIV offers an alternative to conventional clinic-based testing for MSM seeking STI screening. It significantly increases STI testing uptake in HIV infected MSM. HSK could be considered as an adjunct to clinic-based services to further improve STI/HIV testing in MSM
Considerations for Screening Live Kidney Donors for Endemic Infections: A Viewpoint on the UNOS Policy
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/106883/1/ajt12666.pd
Chapter 7 Epilogue: Systems Approaches and Systems Practice
Each of the five systems approaches discussed in this volume: system dynamics (SD), the viable systems model (VSM), strategic options development and analysis (SODA), soft systems methodology (SSM) and critical systems heuristics (CSH) has a pedigree. Not in the sense of the sometimes absurd spectacle of animals paraded at dog shows. Rather, their pedigree derives from their systems foundations, their capacity to evolve and their flexibility in use. None of the five approaches has developed out of use in restricted and controlled contexts of either low or high levels of complicatedness. Neither has any one of them evolved as a consequence of being applied only to situations with either presumed stakeholder agreement on purpose, or courteous disagreement amongst stakeholders, or stakeholder coercion. The compilation is not a celebration of abstract methodologiesâ, but of theoretically robust approaches that have a genuine pedigree in practice
Mechanisms for inclusive governance
How mechanisms for inclusive governance are understood is built on the framing choices that are made about governance and that which is being governed. This chapter unpacks how governance can be understood and considers different historical and contemporary framings of water governance. A framing of âgovernance as praxisâ is developed as a central element in the chapter. What makes governance inclusive is explored, drawing on theoretical, practical and institutional aspects before elucidating some of the different mechanisms currently used or proposed for creating inclusive water governance (though we argue against praxis based on simple mechanism). Finally, the factors that either constrain or enable inclusive water governance are explored with a focus on systemic concepts of learning and feedback
Enabling political legitimacy and conceptual integration for climate change adaptation research within an agricultural bureaucracy: a systemic inquiry
The value of using systems approaches, for situations framed as âsuper wickedâ, is examined from the perspective of research managers and stakeholders in a state-based climate change adaptation (CCA) program (CliChAP). Polycentric drivers influencing the development of CCA research pre-2010 in Victoria, Australia are reflected on, using Soft Systems Methodology (SSM) to generate a boundary critique of CCA research as a human activity system. We experienced the complexity of purpose with research practices pulling in different directions, reflected on the appropriateness of agricultural bureaucraciesâ historical new public management (NPM) practices, and focused on realigning management theory with emerging demands for adaptation research skills and capability. Our analysis conceptualised CliChAP as a subsystem, generating novelty in a wider system, concerned with socio-ecological co-evolution. Constraining/enabling conditions at the time dealing with political legitimacy and conceptual integration were observed as potential catalysts for innovation in research management towards better handling of uncertainty as a social process using systemic thinking in practice (StiP)
Managing systemic change: future roles for social learning systems and communities of practice?
Communication Gaps Associated With DonorâDerived Infections
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/109830/1/ajt12978.pd
A Systemic approach to scoping of factors influencing more sustainable land use in Herefordshire
Defining and putting into practice sustainable land use is a complex, systemic problem. Systems models and techniques were used in a study of Herefordshire to clarify the situation and identify the potential for a more locally focused, learning-based approach to land use. Issues included: (i) uncertainty about the boundary of a 'system of sustainable Herefordshire land use'; (ii) the complexity of economic flows in the county and the absence of some critical data; (iii) the importance of the Herefordshire landscape to tourism and the role of agriculture as a determinant of the state of that landscape; (iv) weakness of the institutional linkage between tourism and agriculture; (v) the current lack of inclusion of many relevant stakeholders in concerted action. Factors favouring a learning approach included a strong local identity, local food-related developments, and educational initiatives. Barriers to such an approach included questions of power and landholding, government policies, and attitudes and skills within organizations. These findings are considered in relation to the wider debate over approaches to sustainability
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