Population dynamics of the zebra mussel (Dreissena polymorpha) in the Hudson River: settlement and post-settlement processes

Submitted in partial fulfillment of contract requirements with NOAA, Semi-Annual Report - October 2004,Report issued on: October 2004INHS Technical Report for submission to: National Oceanic and Atmospheric Administration (NOAA

Managing LTL properties in Event-B refinement

Refinement in Event-B supports the development of systems via proof based step-wise refinement of events. This refinement approach ensures safety properties are preserved, but additional reasoning is required in order to establish liveness and fairness properties. In this paper we present results which allow a closer integration of two formal methods, Event-B and linear temporal logic. In particular we show how a class of temporal logic properties can carry through a refinement chain of machines. Refinement steps can include introduction of new events, event renaming and event splitting. We also identify a general liveness property that holds for the events of the initial system of a refinement chain. The approach will aid developers in enabling them to verify linear temporal logic properties at early stages of a development, knowing they will be preserved at later stages. We illustrate the results via a simple case study

Privacy-Preserving Electronic Ticket Scheme with Attribute-based Credentials

Electronic tickets (e-tickets) are electronic versions of paper tickets, which enable users to access intended services and improve services' efficiency. However, privacy may be a concern of e-ticket users. In this paper, a privacy-preserving electronic ticket scheme with attribute-based credentials is proposed to protect users' privacy and facilitate ticketing based on a user's attributes. Our proposed scheme makes the following contributions: (1) users can buy different tickets from ticket sellers without releasing their exact attributes; (2) two tickets of the same user cannot be linked; (3) a ticket cannot be transferred to another user; (4) a ticket cannot be double spent; (5) the security of the proposed scheme is formally proven and reduced to well known (q-strong Diffie-Hellman) complexity assumption; (6) the scheme has been implemented and its performance empirically evaluated. To the best of our knowledge, our privacy-preserving attribute-based e-ticket scheme is the first one providing these five features. Application areas of our scheme include event or transport tickets where users must convince ticket sellers that their attributes (e.g. age, profession, location) satisfy the ticket price policies to buy discounted tickets. More generally, our scheme can be used in any system where access to services is only dependent on a user's attributes (or entitlements) but not their identities.Comment: 18pages, 6 figures, 2 table

Globalisation and health inequalities: can a human rights paradigm create space for civil society action?

While neoliberal globalisation is associated with increasing inequalities, global integration has simultaneously strengthened the dissemination of human rights discourse across the world. This paper explores the seeming contradiction that globalisation is conceived as disempowering nations states' ability to act in their population's interests, yet implementation of human rights obligations requires effective states to deliver socio-economic entitlements, such as health. Central to the actions required of the state to build a health system based on a human rights approach is the notion of accountability. Two case studies are used to explore the constraints on states meeting their human rights obligations regarding health, the first drawing on data from interviews with parliamentarians responsible for health in East and Southern Africa, and the second reflecting on the response to the HIV/AIDS epidemic in South Africa. The case studies illustrate the importance of a human rights paradigm in strengthening parliamentary oversight over the executive in ways that prioritise pro-poor protections and in increasing leverage for resources for the health sector within parliamentary processes. Further, a rights framework creates the space for civil society action to engage with the legislature to hold public officials accountable and confirms the importance of rights as enabling civil society mobilization, reinforcing community agency to advance health rights for poor communities. In this context, critical assessment of state incapacity to meet claims to health rights raises questions as to the diffusion of accountability rife under modern international aid systems. Such diffusion of accountability opens the door to 'cunning' states to deflect rights claims of their populations. We argue that human rights, as both a normative framework for legal challenges and as a means to create room for active civil society engagement provide a means to contest both the real and the purported constraints imposed by globalisation.Web of Scienc

Lay health workers and HIV programmes: Implications for health systems

One of the consequences of massive investment in antiretroviral access and other AIDS programmes has been the rapid emergence of large numbers of lay workers in the health systems of developing countries. In South Africa, government estimates are 65,000, mostly HIV/TB care-related lay workers contribute their labour in the public health sector, outnumbering the main front-line primary health care providers and professional nurses. The phenomenon has grown organically and incrementally, playing a wide variety of care-giving, support and advocacy roles. Using South Africa as a case, this paper discusses the different forms, traditions and contradictory orientations taken by lay health work and the system-wide effects of a large lay worker presence. As pressures to regularise and formalise the status of lay health workers grow, important questions are raised as to their place in health systems, and more broadly what they represent as a new intermediary layer between state and citizen. It argues for a research agenda that seeks to better characterise types of lay involvement in the health system, particularly in an era of antiretroviral therapy, and which takes a wider perspective on the meanings of this recent re-emergence of an old concept in health systems heavily affected by HIV/AIDS.International Bibliography of Social Science

Measuring Disability Inclusion: Feasibility of Using Existing Multidimensional Poverty Data in South Africa

This paper presents a framework for measuring disability inclusion in order to examine the associations between disability severity and levels of inclusion, provides an example of its operationalization, and assesses the feasibility of using an existing dataset to measure disability inclusion using this framework. Inclusion here refers to the extent to which people with disabilities are accepted and recognized as individuals with authority, enjoy personal relationships, participate in recreation and social activities, have appropriate living conditions, are able to make productive contributions, and have required formal and informal support. Indicators for the operationalization were drawn from the Individual Deprivation Measure South Africa country study and were mapped on to the domains of inclusion (where relevant), and the Washington Group Short Set of questions were used to determine disability status (no, mild, or moderate/severe disability). The analysis indicates that individuals with disabilities experience generally worse outcomes and a comparative lack of inclusion compared to individuals without disabilities, and broadly that those with moderate or severe disabilities experience worse outcomes than those with mild disabilities. This analysis also provides insight into the limitations of using existing datasets for different purposes from their original design