Advanced techniques for the improvement of optical transmission systems

This thesis presents the experimental investigation into two novel techniques which can be incorporated into current optical systems. These techniques have the capability to improve the performance of transmission and the recovery of the transmitted signal at the receiver. The experimental objectives are described and the results for each technique are presented in two sections: The first experimental section is on work related to Ultra-long Raman Fibre lasers (ULRFLs). The fibre lasers have become an important research topic in recent years due to the significant improvement they give over lumped Raman amplification and their potential use in the development of system with large bandwidths and very low losses. The experiments involved the use of ASK and DPSK modulation types over a distance of 240km and DPSK over a distance of 320km. These results are compared to the current state of-the-art and against other types of ultra-long transmission amplification techniques. The second technique investigated involves asymmetrical, or offset, filtering. This technique is important because it deals with the strong filtering regimes that are a part of optical systems and networks in modern high-speed communications. It allows the improvement of the received signal by offsetting the central frequency of a filter after the output of a Delay Line Interferometer (DLI), which induces significant improvement in BER and/or Qvalues at the receiver and therefore an increase in signal quality. The experimental results are then concluded against the objectives of the experimental work and potential future work discussed.

AltitudeOmics: Red Blood Cell metabolic adaptation to high altitude hypoxia

Red blood cells (RBCs) are key players in systemic oxygen transport. RBCs respond to in vitro hypoxia  through  the so-called  oxygen-dependent  metabolic  regulation,  which  involves  the competitive  binding  of  deoxyhemoglobin  and  glycolytic  enzymes  to  the  N-terminal  cytosolic domain  of  band  3.  This  mechanism  promotes  the  accumulation  of  2,3-DPG,  stabilizing  the deoxygenated state of hemoglobin, and cytosol acidification, triggering oxygen off-loading through the  Bohr  effect.  Despite  in  vitro  studies,  in  vivo adaptations  to  hypoxia  have  not  yet  been completely elucidated. Within  the  framework  of  the AltitudeOmics  study,  erythrocytes  were  collected  from  21 healthy volunteers at sea level, after exposure to high altitude (5260m) for 1, 7 and 16days, and following  reascent  after  7days  at 1525m.  UHPLC-MS  metabolomics  results  were  correlated  to physiological and athletic performance parameters. Immediate  metabolic  adaptations  were  noted as early as a few hours from ascending  to >5000m, and maintained for 16 days at high altitude.  Consistent with the mechanisms elucidated in vitro, hypoxia promoted glycolysis and deregulated the pentose phosphate pathway, as well purine catabolism, glutathione homeostasis, arginine/nitric oxide and sulphur/H2S metabolism. Metabolic adaptations were preserved one week after descent, consistently with improved physical performances in comparison to the first ascendance, suggesting a mechanism of metabolic memory.

The impact of leadership and quality climate on hospital performance

Objective. To explore the relationship between leadership effectiveness and health-care trust performance, taking into account external quality measures and the number of patient complaints; also, to examine the role of care quality climate as a mediator. Design. We developed scales for rating leadership effectiveness and care quality climate. We then drew upon UK national indices of health-care trust performance—Commission for Health Improvement star ratings, Clinical Governance Review ratings and the number of patient complaints per thousand. We conducted statistical analysis to examine any significant relationships between predictor and outcome variables. Setting. The study is based on 86 hospital trusts run by the National Health Service (NHS) in the UK. The data collection is part of an annual staff survey commissioned by the NHS to explore the quality of working life. Participants. A total of 17 949 employees were randomly surveyed (41% of the total sample). Results. Leadership effectiveness is associated with higher Clinical Governance Review ratings and Commission for Health Improvement star ratings for our sample (ß = 0.42, P < 0.05; ß = 0.37, P < 0.05, respectively), and lower patient complaints (ß = –0.57, P < 0.05). In addition, 98% of the relationship between leadership and patient complaints is explained by care quality climate. Conclusions. Results offer insight into how non-clinical leadership may foster performance outcomes for health-care organizations. A frequently neglected area—patient complaints—may be a valid measure to consider when assessing leadership and quality in a health-care context.

Aligning employee service recovery performance with brand values:the role of brand-specific leadership

This study investigates the effects of brand-specific leadership on employees' brand-aligned service recovery performance (SRP). In order to do so, we empirically test a conceptual model of relationships between brand-specific transformational leadership (TFL) and transactional leadership (TRL), trust in leader and in corporate brand, brand identification, and SRP from employees' perspectives. It is the first study to incorporate trust in corporate brand into the framework. Results from a study of 246 customer-contact employees show that brand-specific TFL has a positive impact on all variables studied, while brand-specific TRL is ineffective in fostering brand-building behaviours. More specifically, brand-specific TFL's effects on employee SRP are mediated by trust in the leader, trust in the corporate brand, and brand identification. Implications and future research directions are discussed. © 2013 Copyright Taylor & Francis.

Climate change performance measurement, control and accountability in English local areas

Purpose – This paper aims to consider how climate change performance is measured and accounted for within the performance framework for local authority areas in England adopted in 2008. It critically evaluates the design of two mitigation and one adaptation indicators that are most relevant to climate change. Further, the potential for these performance indicators to contribute to climate change mitigation and adaptation is discussed. Design/methodology/approach – The authors begin by examining the importance of the performance framework and the related Local Area Agreements (LAAs), which were negotiated for all local areas in England between central government and Local Strategic Partnerships (LSPs). This development is located within the broader literature relating to new public management. The potential for this framework to assist in delivering the UK's climate change policy objectives is researched in a two-stage process. First, government publications and all 150 LAAs were analysed to identify the level of priority given to the climate change indicators. Second, interviews were conducted in spring 2009 with civil servants and local authority officials from the English West Midlands who were engaged in negotiating the climate change content of the LAAs. Findings – Nationally, the authors find that 97 per cent of LAAs included at least one climate change indicator as a priority. The indicators themselves, however, are perceived to be problematic – in terms of appropriateness, accuracy and timeliness. In addition, concerns were identified about the level of local control over the drivers of climate change performance and, therefore, a question is raised as to how LSPs can be held accountable for this. On a more positive note, for those concerned about climate change, the authors do find evidence that the inclusion of these indicators within the performance framework has helped to move climate change up the agenda for local authorities and their partners. However, actions by the UK's new coalition government to abolish the national performance framework and substantially reduce public expenditure potentially threaten this advance. Originality/value – This paper offers an insight into a new development for measuring climate change performance at a local level, which is relatively under-researched. It also contributes to knowledge of accountability within a local government setting and provides a reference point for further research into the potential role of local actions to address the issue of climate change.