919 resultados para Advent.


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In this contribution I look at three episodes in the history of neurophysiology that bring out the complex relationship between seeing and believing. I start with Vesalius in the mid-sixteenth century who writes that he can in no way see any cavity in nerves, even in the optic nerves. He thus questions the age-old theory (dating back to the Alexandrians in the third century BC) but, because of the overarching psychophysiology of his time, does not press his case. This conflict between observation and theory persisted for a quarter of a millennium until finally resolved at the beginning of the nineteenth century by the discoveries of Galvani and Volta. The second case is provided by the early history of retinal synaptology. Schultze in 1866 had represented rod spherules and bipolar dendrites in the outer plexiform layer as being separated by a (synaptic) gap, yet in his written account, because of his theoretical commitments, held them to be continuous. Cajal later, 1892, criticized Schultze for this pusillanimity, but his own figure in La Cellule is by no means clear. It was only with the advent of the electron microscopy in the mid-twentieth century that the true complexity of the junction was revealed and it was shown that both investigators were partially right. My final example comes from the Hodgkin-Huxley biophysics of the 1950s. Their theory of the action potential depended on the existence of unseen ion pores with quite complex biophysical characteristics. These were not seen until the Nobel-Prize-winning X-ray diffraction analyses of the early twenty-first century. Seeing, even at several removes, then confirmed Hodgkin and Huxley’s belief. The relation between seeing and believing is by no means straightforward.

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Since the advent of High Level Programming languages (HLPLs) in the early 1950s researchers have sought ways to automate the construction of HLPL compilers. To this end a variety of Translator Writing Tools (TWTs) have been developed in the last three decades. However, only a very few of these tools have gained significant commercial acceptance. This thesis re-examines traditional compiler construction techniques, along with a number of previous TWTs, and proposes a new improved tool for automated compiler construction called the Aston Compiler Constructor (ACC). This new tool allows the specification of complete compilation systems using a high level compiler oriented specification notation called the Compiler Construction Language (CCL). This specification notation is based on a modern variant of Backus Naur Form (BNF) and an extended variant of Attribute Grammars (AGs). The implementation and processing of the CCL is discussed along with an extensive CCL example. The CCL is shown to have an extensive expressive power, to be convenient in use, and highly readable, and thus a superior alternative to earlier TWTs, and to traditional compiler construction techniques. The execution performance of CCL specifications is evaluated and shown to be acceptable. A number of related areas are also addressed, including tools for the rapid construction of individual compiler components, and tools for the construction of compilation systems for multiprocessor operating systems and hardware. This latter area is expected to become of particular interest in future years due to the anticipated increased use of multiprocessor architectures.

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With the advent of distributed computer systems with a largely transparent user interface, new questions have arisen regarding the management of such an environment by an operating system. One fertile area of research is that of load balancing, which attempts to improve system performance by redistributing the workload submitted to the system by the users. Early work in this field concentrated on static placement of computational objects to improve performance, given prior knowledge of process behaviour. More recently this has evolved into studying dynamic load balancing with process migration, thus allowing the system to adapt to varying loads. In this thesis, we describe a simulated system which facilitates experimentation with various load balancing algorithms. The system runs under UNIX and provides functions for user processes to communicate through software ports; processes reside on simulated homogeneous processors, connected by a user-specified topology, and a mechanism is included to allow migration of a process from one processor to another. We present the results of a study of adaptive load balancing algorithms, conducted using the aforementioned simulated system, under varying conditions; these results show the relative merits of different approaches to the load balancing problem, and we analyse the trade-offs between them. Following from this study, we present further novel modifications to suggested algorithms, and show their effects on system performance.

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The central argument to this thesis is that the nature and purpose of corporate reporting has changed over time to become a more outward looking and forward looking document designed to promote the company and its performance to a wide range of shareholders, rather than merely to report to its owners upon past performance. it is argued that the discourse of environmental accounting and reporting is one driver for this change but that this discourse has been set up as in conflicting with the discourse of traditional accounting and performance measurement. The effect of this opposition between the discourses is that the two have been interpreted to be different and incompatible dimensions of performance with good performance along one dimension only being achievable through a sacrifice of performance along the other dimension. Thus a perceived dialectic in performance is believed to exist. One of the principal purposes of this thesis is to explore this perceived dialectic and, through analysis, to show that it does not exist and that there is not incompatibility. This exploration and analysis is based upon an investigation of the inherent inconsistencies in such corporate reports and the analysis makes use of both a statistical analysis and a semiotic analysis of corporate reports and the reported performance of companies along these dimensions. Thus the development of a semiology of corporate reporting is one of the significant outcomes of this thesis. A further outcome is a consideration of the implications of the analysis for corporate performance and its measurement. The thesis concludes with a consideration of the way in which the advent of electronic reporting may affect the ability of organisations to maintain the dialectic and the implications for corporate reporting.

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This thesis presents a number of methodological developments that were raised by a real life application to measuring the efficiency of bank branches. The advent of internet banking and phone banking is changing the role of bank branches from a predominantly transaction-based one to a sales-oriented role. This fact requires the development of new forms of assessing and comparing branches of a bank. In addition, performance assessment models must also take into account the fact that bank branches are service and for-profit organisations to which providing adequate service quality as well as being profitable are crucial objectives. This study analyses bank branches performance in their new roles in three different areas: their effectiveness in fostering the use of new transaction channels such as the internet and the telephone (transactional efficiency); their effectiveness in increasing sales and their customer base (operational efficiency); and their effectiveness in generating profits without compromising the quality of service (profit efficiency). The chosen methodology for the overall analysis is Data Envelopment Analysis (DEA). The application attempted here required some adaptations to existing DEA models and indeed some new models so that some specialities of our data could be handled. These concern the development of models that can account for negative data, the development of models to measure profit efficiency, and the development of models that yield production units with targets that are nearer to their observed levels than targets yielded by traditional DEA models. The application of the developed models to a sample of Portuguese bank branches allowed their classification according to the three performance dimensions (transactional, operational and profit efficiency). It also provided useful insights to bank managers regarding how bank branches compare between themselves in terms of their performance, and how, in general, the three performance dimensions are connected between themselves.

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The advent of DNA vaccines has heralded a new technology allowing the design and elicitation of immune responses more adequate for a wider range of pathogens. The formulation of these vaccines into the desired dosage forms extends their capability in terms of stability, routes of administration and efficacy. This thesis describes an investigation into the fabrication of plasmid DNA, the active principle of DNA vaccines, into microspheres, based on the tenet of an increased cellular uptake of microparticulate matter by phagocytic cells. The formulation of plasmid DNA into microspheres using two methods, is presented. Formulation of microspheric plasmid DNA using the double emulsion solvent evaporation method and a spray-drying method was explored. The former approach involves formation of a double emulsion, by homogenisation. This method produced microspheres of uniform size and smooth morphology, but had a detrimental effect on the formulated DNA. The spray-drying method resulted in microspheres with an improved preservation of DNA stability. The use of polyethylenimine (PEI) and stearylamine (SA) as agents in the microspheric formulation of plasmid DNA is a novel approach to DNA vaccine design. Using these molecules as model positively-charged agents, their influence on the characteristics of the microspheric formulations was investigated. PEI improved the entrapment efficiency of the plasmid DNA in microspheres, and has minimal effect on either the surface charge, morphology or size distribution of the formulations. Stearylamine effected an increase in the entrapment efficiency and stability of the plasmid DNA and its effect on the micropshere morphology was dependent on the method of preparation. The differences in the effects of the two molecules on microsphere formulations may be attributable to their dissimilar physico-chemical properties. PEI is water-soluble and highly-branched, while SA is hydrophobic and amphipathic. The positive charge of both molecules is imparted by amine functional groups. Preliminary data on the in vivo application of formulated DNA vaccine, using hepatitis B plasmid, showed superior humoral responses to the formulated antigen, compared with free (unformulated) antigen.

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The introduction of a micro-electronic based technology to the workplace has had a far reaching and widespread effect on the numbers and content of jobs. The importance of the implications of new technology were recognised by the trade unions, leading to a plethora of advice and literature in the late 70s and early 80s, notably the TUC 'Technology and Employment ' report. However, studies into the union response have consistently found an overall lack of influence by unions in the introduction of technology. Whilst the advent of new technology has coincided with an industrial relations climate of unprecedented hostility to union activity in the post-war period, there are structural weaknesses in unions in coming to terms with the process of technological change. In particular was the identification of a lack of suitable technological expertise. Addressing itself to this perceived weakness of the union response, this thesis is the outcome of a collaborative project between a national union and an academic institution. The thesis is based on detailed case studies concerning technology bargaining in the Civil Service and the response of the Civil and Public Services Associations (CPSA), the union that represents lower grade white collar civil servants. It is demonstrated that the application of expertise to union negotiators is insufficient on its own to extend union influence and that for unions to effectively come to terms with technology and influence its development requires a re-assessment across all spheres of union activity. It is suggested that this has repercussions for not only the internal organisation and quality of union policy formation and the extent, form and nature of collective bargaining with employer representatives, but also in the relationship with consumer and interest groups outside the traditional collective bargaining forum. Three policy options are developed in the thesis with the 'adversarial' and 'co~operative' options representing the more traditional reactive and passive forms of involvement. These are contrasted with an 'independent participative' form of involvement which was a 'pro-active' policy option and utilised the expertise of the Author in the CPSA's response to technological change.

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The advent of the harmonic neutralised shunt Converter Compensator as a practical means of reactive power compensation in power transmission systems has cleared ground for wider application of this type of equipment. An experimental 24-pulse voltage sourced convector has been successfully applied in controlling the terminal power factor of a 1.5kW, 240V three phase cage rotor induction motor, whose winding has been used in place of the usual phase shifting transformers. To achieve this, modifications have been made to the conventional stator winding of the induction machine. These include an unconventional phase spread and facilitation of compensator connections to selected tapping points between stator coils to give a three phase winding with a twelve phase connection to the twenty four pulse converter. Theoretical and experimental assessments of the impact of these modifications and attachment of the compensator have shown that there is a slight reduction in the torque developed at a given slip and in the combined system efficiency. There is also an increase in the noise level, also a consequence of the harmonics. The stator leakage inductance gave inadequate coupling reactance between the converter and the effective voltage source, necessitating the use of external inductors in each of the twelve phases. The terminal power factor is fully controllable when the induction machine is used either as a motor or as a generator.

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There is a great deal of literature about the initial stages of innovative design. This is the process whereby a completely new product is conceived, invented and developed. In industry, however, the continuing success of a company is more often achieved by improving or developing existing designs to maintain their marketability. Unfortunately, this process of design by evolution is less well documented. This thesis reports the way in which this process was improved for the sponsoring company. The improvements were achieved by implementing a new form of computer aided design (C.A.D.) system. The advent of this system enabled the company to both shorten the design and development time and also to review the principles underlying the existing design procedures. C.A.D. was a new venture for the company and care had to be taken to ensure that the new procedures were compatible with the existing design office environment. In particular, they had to be acceptable to the design office staff. The C.A.D. system produced guides the designer from the draft specification to the first prototype layout. The computer presents the consequences of the designer's decisions clearly and fully, often by producing charts and sketches. The C.A.D. system and the necessary peripheral facilities were implemented, monitored and maintained. The system structure was left sufficiently flexible for maintenance to be undertaken quickly and effectively. The problems encountered during implementation are well documented in this thesis.

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Over the years several articles have tracked the impact of technology on various aspects of the sales domain. However, the advent of social media and technologies related to social media has gone largely unnoticed in the literature. This article first provides brief attention to changing aspects of technology within the sales environment, leading to the identification of social media as a dominant new selling tool. A qualitative approach (focus groups) is employed to explore the breadth of current technology usage by sales managers and salespeople. Analysis of the data, collected in the United States and the United Kingdom, reveals six major themes: connectivity, relationships, selling tools, generational, global, and sales/marketing interface. Results provide evidence of a revolution in the buyer-seller relationship that includes some unanticipated consequences both for sales organization performance and needed future research contributions.

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Pharmacy originates from a background of medication compounding and supply. More recently, this role has developed away from an absolute focus on the supply of pharmaceuticals with, for example, the advent of pharmacist prescribing. Nevertheless, for a majority of the profession, medication supply remains a core activity. Regulation of the pharmacy profession is now the responsibility of the General Pharmaceutical Council, although up until 27 September 2010, this role fell to the Royal Pharmaceutical Society of Great Britain (RPSGB). Before this change, in one of the most high-profile legal cases involving a pharmacist in a professional capacity, R. v Lee, a pharmacist was prosecuted firstly for gross negligence manslaughter, later revised to offences under the Medicines Act 1968, for a single error relating to medication supply, and was given a suspended custodial sentence. Offences against sections 64 or 85 of the Medicines Act are absolute offences and there is no due diligence defence. Prosecution of a pharmacist for the supply of incorrect medication may seem a measured course of action to protect the public from the wrongful supply of potent pharmacotherapeutic agents; however, further analysis of Lee indicates that this approach may be counterproductive. An appeal of the original conviction in the Lee case has resulted in a clarification of the interpretation of section 85(5); however currently, prosecutions under section 64 are still a possibility. Owing to the seriousness of a criminal conviction under section 64, this continuation will potentially stifle the profession's ability to learn from dispensing errors. © The Author [2013]. Published by Oxford University Press; all rights reserved.

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What is meant by the term ‘specialist contact lens fitting’? Or put another way, what would be considered non-specialist contact lens fitting? Is there such a thing as routine contact lens fitting? Soft or silicone hydrogel fitting for daily wear would probably be considered as routine contact lens fitting, but would extended or flexible wear remain in the same category or would they be considered a specialist fit? Different eras will classify different products as being ‘specialist’. Certainly twenty years ago soft toric contact lenses were considered as being speciality lenses but today would be thought of as routine lenses. Conversely, gas permeable lenses were thought of as mainstream twenty years ago but now are considered as speciality lenses. Although this would not be the same globally, as in some countries (such as Netherlands, France and Japan) gas permeable lens fitting remains popular and is not on the decline as in other countries (Canada, Australia and Sweden) [1]. Bandage soft lenses applied after surface laser refractive procedures would be considered as therapeutic lenses but in reality they are just plano thin hydrogel lenses worn constantly for 3–4 days to allow the underlying epithelium to convalesce and are then removed [2]. Some patients find that wearing hydrogel lenses during periods when they suffer from seasonal allergies actually improves their ocular comfort as the contact lens acts as a barrier to the allergen [3] and [4]. Scleral lenses have long been considered speciality lenses, apart from a time when they were the only lenses available but at that time all contact lens work would have been considered speciality practice! Nowadays we see the advent of mini-scleral designs and we see large diameter gas permeable lenses too. It is possible that these lenses increase the popularity of gas permeable lenses again and they become more main stream. So it would seem that the lines between routine and speciality contact lens fitting are not clear. Whether a lens is classed a specialist fit or not would depend on the lens type, why it was fitted, where in the world the fitting was being done and even the era in which it was fitted. This begs the question as to what would be considered entry level knowledge in contact lens fitting. This may not be an issue for most BCLA members or CLAE readers but certainly would be for bodies such as the College of Optometrists (UK) or the Association of British Dispensing Opticians when they are planning the final registration examinations for budding practitioners or when planning the level of higher level qualifications such as College Certificates or Diplomas. Similarly for training institutions when they are planning their course content. This becomes even trickier when trying to devise a qualification that spans across many countries, like the European Diploma in Optometry and Optics. How do we know if the training and examination level is correct? One way would be to analyse things when they go wrong and if patterns of malpractice are seen then maybe that could be used as an indicator to more training being needed. There were 162 Fitness to Practice Hearing at the General Optical Council between 2001 and 2010. Forty-seven of these were clinically related case, 39 fraud related, and 76 others. Of the clinical ones only 3 were contact lens related. So it would appear that as whole, in the profession, contact lens clinical skills are not being questioned too often (although it seems a few of us can’t keep our hands out the cookie jar!).

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The advent of the internet has led to the new phenomenon of ‘cyberstalking’. This paper examines the extent of this problem. It is argued that all of the estimates commonly cited are flawed because they rely on inaccurate or outdated information or are based on a number of unproven assumptions. Although some estimates suggest that there may be as many as 10 million victims in the United States and Canada alone, available evidence supports a far smaller estimate. It is concluded that additional research is needed to arrive at more accurate and reliable estimates

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The treatment of choroidal neovascularisation (CNV) secondary to pathological myopia has presented a number of problems to ophthalmologists over the years, but the advent of photodynamic therapy (PDT) with verteporfin has changed how we manage these patients. Until PDT became available, the use of laser photocoagulation for extra and juxtafoveal lesions had been shown to be effective in the short term in preventing loss of vision, although the risk of regrowth of CNV and undertreatment were well recognised. However, even in apparent successful cases of photocoagulation, laser scar enlargement and creepage into the fovea in the mid-to-long term often occurred with resulting loss of central vision.1 Other options for treatment were very limited with little evidence that other modalities such as transpupillary thermotherapy or submacular surgery and macular transplantation surgery would be successful in highly myopic eyes. The evidence for the role of PDT and verteporfin CNV secondary to pathological myopia comes from the verteporfin in photodynamic therapy (VIP) study that has shown how effective this treatment is in eyes with subfoveal CNV.2, 3 Now in this publication, Lam et al4 from Hong Kong have shown that PDT is also effective in juxtafoveal CNV, with high myopia. They performed a small prospective study of 11 patients of mean age 44.8 years, with 12 months of follow-up. They found that there was a mean improvement of 1.8 lines of LogMAR best-corrected visual acuity (BCVA) at 12 months, with a mean number of 2.3 PDT treatments. The most rapid improvement occurred within the first 3 months of treatment and by 12 months none of the patients had suffered a deterioration in BCVA from baseline. There were no cases of adverse effects from the infusion or laser treatment. For ophthalmologists dealing with patients with CNV secondary to causes other than AMD, this is further evidence of the effectiveness of PDT with verteporfin in maintaining vision. These patients are likely to be younger than those with AMD and are likely to be in active employment and supporting families, and clearly the preservation of best vision possible is imperative in this group. It is therefore encouraging for ophthalmologists in the United Kingdom that the verteporfin in PDT Cohort Study (VPDT Study) includes the ability to treat patients with subfoveal CNV secondary to high myopia if they fulfill National Institute of Clinical Excellence guidelines, and will allow representations to be made on an individual basis for treatment of juxtafoveal lesions.5 For those ophthalmologists used to juggling increased patient expectations with scarce NHS resources, this is promising news and will allow us to offer a better standard of care to our patients.

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After about a quarter of a century of enlightened development and ongoing preparatory technological, scientific and political activities we are arrived at the realization period of the idea. The two major technological vehicles of progress are the World Wide Web, the most democratic international forum of information exchange and the advent of public key cryptography as a combined philosophical and practical device of individual integrity and collective responsibility.