Forward Error Correction in Memoryless Optical Modulation

The unprecedented growth in demand for digital media has led to an all-time high in society’s demand for information. This demand will in all likelihood continue to grow as technology such as 3D television service, on-demand video and peer-to-peer networking continue to become more common place. The large amount of information required is currently transmitted optically using a wavelength division multiplexing (WDM) network structure. The need to increase the capacity of the existing WDM network infrastructure efficiently is essential to continue to provide new high bandwidth services to end-users, while at the same time minimizing network providers’ costs. In WDM systems the key to reducing the cost per transported information bit is to effectively share all optical components. These components must operate within the same wavelength limited window; therefore it is necessary to place the WDM channels as close together as possible. At the same time, the correct modulation format must be selected in order to create flexible, cost-effective, high-capacity optical networks. This thesis presents a detailed comparison of Differential Quadrature Phase Shift Keying (DQPSK) to other modulation formats. This comparison is implemented through a series of simulations in which the bit error rate of various modulation formats are compared both with and without the presence of forward error correction techniques. Based off of these simulation results, the top performing modulation formats are placed into a multiplexed simulation to assess their overall robustness in the face of multiple filtering impairments

Custom and habit(us): The meaning of traditions and legends in early medieval western Britain

This a post-print, author-produced version of an article accepted for publication in Geografiska Annaler, Series B: Human Geography. Copyright © Blackwell publishing 1999. The definitive version is available at www.blackwell-synergy.comThis paper discusses some well-known legends and hagiographic stories, and explores the context of their production and consumption. From an examination of Welsh foundation legends and Cornish hagiographical accounts, we focus on the methods by which versions of history were used in the Middle Ages to provide a context for fundamental changes in the way in which society was organised. It is found that, far from abandoning traditional versions of history, accounts of the past were promoted that sought to couch newer territorial notions of organisation within existing constructions of identity and mediations with the past. In an examination of the production and reception of these popular stories, we attempt to relate the legends to the generation of communal identity and memory. Consequently, drawing on Bourdieu's notion of habitus, we argue that pre-existing beliefs and customs were an important part in the development of newer institutional structures. Rather than initiating new practices that had no grounding in any particular past, institutional developments gained social currency by being inherently grounded in existing facets of cultural identity. In essence therefore, changing societal and institutional structures were unintentionally couched in the language and understandings of existing structures, so that in many ways a concept of continuity was at the very heart of actual change

An analysis of coastal zone management in England and the Netherlands

The coastal zone is an area of crucial economic and ecological significance, which has increasingly been recognised in land-use planning. Within the coastal zone, integrating land-use planning and environmental management is recognised as one way to minimise trade-offs of interest between economic development and environmental objectives. Many governments are currently discussing the potential role of integrated coastal zone management (CZM) within their planning systems, while some international organisations promote CZM as a means to counter the loss of coastal resources due to human occupation of the coast.This thesis examines how the coastal zone in the United Kingdom is perceived and how effectively CZM is being promoted as a planning model to secure sustainable coastal development through the integration of planning policies. Policy integration is not a quixotic quest, but a model suggesting appropriate methods to manage and reduce conflicts. Any planning model can be traceable to varying assumptions and propositions from political thought, which in turn arises from different political practices. Each CZM plan thus reflects the planning and policy culture of its national system.In order to provide a context within which to assess the UK approach, the development of CZM in the Netherlands is also examined. Both national planning systems have comprehensive statutory land-use planning systems, while marine issues are controlled sectorally by central government. Neither administration has a national CZM policy framework. This thesis therefore includes a comparison of two management plans: the Wash Estuary Management Plan and Integraal Beleidsplan Voordelta. By comparing the organisational structures, policy development and implementation, the case studies provide an insight into the national CZM planning strategy currently being followed in the UK. Finally, the thesis concludes by identifying ways in which CZM might be further improved in the UK and also integrated into European approaches that have recently been initiated

A Camelid Anti-PrP Antibody Abrogates PrPSc Replication in Prion-Permissive Neuroblastoma Cell Lines

The development of antibodies effective in crossing the blood brain barrier (BBB), capable of accessing the cytosol of affected cells and with higher affinity for PrPSc would be of paramount importance in arresting disease progression in its late stage and treating individuals with prion diseases. Antibody-based therapy appears to be the most promising approach following the exciting report from White and colleagues, establishing the “proof-of-principle” for prion-immunotherapy. After passive transfer, anti-prion antibodies were shown to be very effective in curing peripheral but not central rodent prion disease, due to the fact that these anti-prion antibodies are relatively large molecules and cannot therefore cross the BBB. Here, we show that an anti-prion antibody derived from camel immunised with murine scrapie material adsorbed to immunomagnetic beads is able to prevent infection of susceptible N2a cells and cure chronically scrapie-infected neuroblastoma cultures. This antibody was also shown to transmigrate across the BBB and cross the plasma membrane of neurons to target cytosolic PrPC. In contrast, treatment with a conventional anti-prion antibody derived from mouse immunised with recombinant PrP protein was unable to prevent recurrence of PrPSc replication. Furthermore, our camelid antibody did not display any neurotoxic effects following treatment of susceptible N2a cells as evidenced by TUNEL staining. These findings demonstrate the potential use of anti-prion camelid antibodies for the treatment of prion and other related diseases via non-invasive means

Educating for Indigenous health equity: An international consensus statement

The determinants of health inequities between Indigenous and non-Indigenous populations include factors amenable to medical education’s influence, for example, the competence of the medical workforce to provide effective and equitable care to Indigenous populations. Medical education institutions have an important role to play in eliminating these inequities. However, there is evidence that medical education is not adequately fulfilling this role, and in fact may be complicit in perpetuating inequities. This article seeks to examine the factors underpinning medical education’s role in Indigenous health inequity, in order to inform interventions to address these factors. The authors developed a consensus statement that synthesizes evidence from research, evaluation, and the collective experience of an international research collaboration including experts in Indigenous medical education. The statement describes foundational processes that limit Indigenous health development in medical education and articulates key principles that can be applied at multiple levels to advance Indigenous health equity. The authors recognize colonization, racism, and privilege as fundamental determinants of Indigenous health that are also deeply embedded in Western medical education. In order to contribute effectively to Indigenous health development, medical education institutions must engage in decolonization processes and address racism and privilege at curricular and institutional levels. Indigenous health curricula must be formalized and comprehensive, and must be consistently reinforced in all educational environments. Institutions’ responsibilities extend to advocacy for health system and broader societal reform to reduce and eliminate health inequities. These activities must be adequately resourced and underpinned by investment in infrastructure and Indigenous leadership