Reading performance with various lamps in age-related macular degeneration

The purpose of this study was to determine if there was an objective difference in reading between four commonly available lamps, of varying spectral radiance, for 13 subjects with age-related maculopathy (ARM) or non-exudative age-related macular degeneration (AMD) - logMAR visual acuity between 0.04 and 0.68. At a constant illuminance of 2000 lux, there was no interaction between ARM and AMD subgroups and no statistically significant difference between the lamps: standard (clear envelope) incandescent, daylight simulation (blue tint envelope) incandescent, compact fluorescent and halogen incandescent, for any reading outcome measure (threshold print size p = 0.67, critical print size p = 0.74, acuity reserve p = 0.84 and mean reading rate p = 0.78). For lamps typically used in low-vision rehabilitation, a clinically significant effect of spectral radiance on reading for people with ARM or non-exudative AMD is unlikely. © 2007 The College of Optometrists.

Real-time process plant fault diagnosis

Operators can become confused while diagnosing faults in process plant while in operation. This may prevent remedial actions being taken before hazardous consequences can occur. The work in this thesis proposes a method to aid plant operators in systematically finding the causes of any fault in the process plant. A computer aided fault diagnosis package has been developed for use on the widely available IBM PC compatible microcomputer. The program displays a coloured diagram of a fault tree on the VDU of the microcomputer, so that the operator can see the link between the fault and its causes. The consequences of the fault and the causes of the fault are also shown to provide a warning of what may happen if the fault is not remedied. The cause and effect data needed by the package are obtained from a hazard and operability (HAZOP) study on the process plant. The result of the HAZOP study is recorded as cause and symptom equations which are translated into a data structure and stored in the computer as a file for the package to access. Probability values are assigned to the events that constitute the basic causes of any deviation. From these probability values, the a priori probabilities of occurrence of other events are evaluated. A top-down recursive algorithm, called TDRA, for evaluating the probability of every event in a fault tree has been developed. From the a priori probabilities, the conditional probabilities of the causes of the fault are then evaluated using Bayes' conditional probability theorem. The posteriori probability values could then be used by the operators to check in an orderly manner the cause of the fault. The package has been tested using the results of a HAZOP study on a pilot distillation plant. The results from the test show how easy it is to trace the chain of events that leads to the primary cause of a fault. This method could be applied in a real process environment.

Reliability analysis for hazard and operability studies

Fault tree analysis is used as a tool within hazard and operability (Hazop) studies. The present study proposes a new methodology for obtaining the exact TOP event probability of coherent fault trees. The technique uses a top-down approach similar to that of FATRAM. This new Fault Tree Disjoint Reduction Algorithm resolves all the intermediate events in the tree except OR gates with basic event inputs so that a near minimal cut sets expression is obtained. Then Bennetts' disjoint technique is applied and remaining OR gates are resolved. The technique has been found to be appropriate as an alternative to Monte Carlo simulation methods when rare events are countered and exact results are needed. The algorithm has been developed in FORTRAN 77 on the Perq workstation as an addition to the Aston Hazop package. The Perq graphical environment enabled a friendly user interface to be created. The total package takes as its input cause and symptom equations using Lihou's form of coding and produces both drawings of fault trees and the Boolean sum of products expression into which reliability data can be substituted directly.

Remote sensing applied to land use and erosion hazard studies in Jamaica

The northern half of the parish of St. Catherine in Jamaica was selected as a test area to study, by means of remote sensing, the problems of soil erosion in a tropical environment. An initial study was carried out to determine whether eroded land within this environment could be successfully interpreted and mapped from the available 1: 25,000 scale aerial photographs. When satisfied that a sufficiently high percentage of the eroded land could be interpreted on the aerial photographs the main study was initiated. This involved interpreting the air photo cover of the study area for identifying and classifying land use and eroded land, and plotting the results on overlays on topographic base maps. These overlays were then composited with data on the soils and slopes of the study area. The areas of different soil type/slope/land use combinations were then measured, as was the area of eroded land for each of these combinations. This data was then analysed in two ways. The first way involved determining which of the combinations of soil type, slope and land use were most and least eroded and, on the basis of this, to draw up recommendations concerning future land use. The second analysis was aimed at determining which of the three factors, soil type, slope and land use, was most responsible for determining the rate of erosion. Although it was possible to show that slope was not very significant in determining the rate of erosion, it was much more difficult to separate the effects of land use and soil type. The results do, however, suggest that land use is more significant than soil type in determining the rate of erosion within the study area.

The formation and impact of hazard control policy:a study of the regulation of white lead paint in Britain

Government regulation of industrial hazards is examined in the context of the economic and technical processes of industrial development. Technical problems and costs of control are considered as factors in both the formation and impact of regulation. This thesis focuses on an historical case-study of the regulation of the hazard to painting workers from the use of lead pigments in paint. A regulatory strategy based on the prohibition of lead paints gained initial acceptance within the British state in 1911, but was subsequently rejected in favour of a strategy that allowed continued use of lead paint subject to hygiene precautions. The development of paint technology and its determinants, including concern about health hazards, are analysed, focusing on the innovation and diffusion into the paint industry of the major white pigments: white lead (PbC03 .PB(OH)2)and its substitutes. The process of regulatory development is examined, and the protracted and polarised regulatory d~bate contrasted to the prevailing 'consensual' methods of workplace regulation. The rejection of prohibition is analysed in terms of the different political and technical resources of those groups in conflict over this policy. This highlights the problems of consensus formation around such a strategy, and demonstrates certain constraints on state regulatory activity, particularly regarding industrial development. Member-states of the International Labour Organisation agreed to introduce partial prohibition of lead paint in 1921. Whether this was implemented is related to the economic importance of lead and non-lead metal and pigment industries to a nation. An analysis is made of the control of lead poisoning. The rate of control is related to the economic and technological trajectory of the regulated industry. Technical and organisational characteristics are considered as well as regulatory factors which range from voluntary compliance and informal pressures to direct legal requirements. The implications of this case-study for the analysis of the development and impacts of regulation are assessed.

A comparison of the impact of avoidance cues in hazard avoidance during evaluation of text entry

The research presented in this paper is part of an ongoing investigation into how best to support meaningful lab-based evaluations of mobile technologies. In our previous work, we developed a hazard avoidance system for use during lab evaluations [1]; in the work reported here, we further assess the impact of this system, specifically in terms of the effect of avoidance cue type on speech-based text entry tasks.

A comparison of the impact of avoidance cues in hazard avoidance during evaluation of text entry

The research presented in this paper is part of an ongoing investigation into how best to support meaningful lab-based evaluations of mobile technologies. In our previous work, we developed a hazard avoidance system for use during lab evaluations [1]; in the work reported here, we further assess the impact of this system, specifically in terms of the effect of avoidance cue type on speech-based text entry tasks.

Disseminating a warning message to evacuate:a simulation study of the behaviour of neighbours

Large-scale evacuations are a recurring theme on news channels, whether in response to major natural or manmade disasters. The role of warning dissemination is a key part in the success of such large-scale evacuations and its inadequacy in certain cases has been a 'primary contribution to deaths and injuries' (Hayden et al.; 2007). Along with technology-driven 'official warning channels' (e.g. sirens, mass media), the role of unofficial channel (e.g. neighbours, personal contacts, volunteer wardens) has proven to be significant in warning the public of the need to evacuate. Although post-evacuation studies identify the behaviours of evacuees as disseminators of the warning message, there has not been a detailed study that quantifies the effects of such behaviour on the warning message dissemination. This paper develops an Agent-Based Simulation (ABS) model of multiple agents (evacuee households) in a hypothetical community to investigate the impact of behaviour as an unofficial channel on the overall warning dissemination. Parameters studied include the percentage of people who warn their neighbours, the efficiency of different official warning channels, and delay time to warn neighbours. Even with a low proportion of people willing to warn their neighbour, the results showed considerable impact on the overall warning dissemination. © 2012 Elsevier B.V. All rights reserved.

Informal dissemination scenarios and the effectiveness of evacuation warning dissemination of households:a simulation study

Timely warning of the public during large scale emergencies is essential to ensure safety and save lives. This ongoing study proposes an agent-based simulation model to simulate the warning message dissemination among the public considering both official channels and unofficial channels The proposed model was developed in NetLogo software for a hypothetical area, and requires input parameters such as effectiveness of each official source (%), estimated time to begin informing others, estimated time to inform others and estimated percentage of people (who do not relay the message). This paper demonstrates a means of factoring the behaviour of the public as informants into estimating the effectiveness of warningdissemination during large scale emergencies. The model provides a tool for the practitioner to test the potential impact of the informal channels on the overall warning time and sensitivity of the modelling parameters. The tool would help the practitioners to persuade evacuees to disseminate the warning message informing others similar to the ’Run to thy neighbour campaign conducted by the Red cross.

Moral hazard, dividends, and risk in banks

In non-financial firms, higher risk taking results in lower dividend payout ratios. In banking, public guarantees may result in a positive relationship between dividend payout ratios and risk taking. I investigate the interplay between dividend payout ratios and bank risk-taking allowing for the effect of charter values and capital adequacy regulation. I find a positive relationship between bank risk-taking and dividend payout ratios. Proximity to the required capital ratio and a high charter value reduce the impact of bank risk-taking on the dividend payout ratio. My results are robust to different proxies for the dividend payout ratio and bank risk-taking. © 2014 John Wiley & Sons Ltd.

State subsidy and moral hazard in corporate financing

This paper investigates the impact of state subsidy on the behavior of the entrepreneur under asymmetric information. Several authors formulated concerns about state intervention as it can aggravate moral hazard in corporate financing. In the seminal paper of Holmström and Tirole (1997) a two-player moral hazard model is presented with an entrepreneur initiating a risky scalable project and a private investor (e.g. bank or venture capitalist) providing outside financing. The novelty of our research is that this basic moral hazard model is extended to the case of positive externalities and to three players by introducing the state subsidizing the project. It is shown that in the optimum, state subsidy does not harm, but improves the incentives of the entrepreneur to make efforts for the success of the project; hence in effect state intervention reduces moral hazard. Consequently, state subsidy increases social welfare which is defined as the sum of private and public net benefits. Also, the exact form of the state subsidy (ex-ante/ex-post, conditional/unconditional, refundable/nonrefundable) is irrelevant in respect of the optimal size and the total welfare effect of the project. Moreover, in case of nonrefundable subsidies state does not crowd out private investors; but on the contrary, by providing additional capital it boosts private financing. In case of refundable subsidies some crowding effects may occur depending on the subsidy form and the parameters.

Disaster Risk Management Disparity in the Caribbean: Evidence from Barbados, Dominican Republic, Jamaica and Trinidad and Tobago

This study on risk and disaster management capacities of four Caribbean countries: Barbados, the Dominican Republic, Jamaica, and Trinidad and Tobago, examines three main dimensions: 1) the impact of natural disasters from 1900 to 2010 (number of events, number of people killed, total number affected, and damage in US$); 2) institutional assessments of disaster risk management disparity; and 3) the 2010 Inter-American Bank for Development (IADB) Disaster Risk and Risk Management indicators for the countries under study. The results show high consistency among the different sources examined, pointing out the need to extend the IADB measurements to the rest of the Caribbean countries. Indexes and indicators constitute a comparison measure vis-à-vis existing benchmarks in order to anticipate a capacity to deal with adverse events and their consequences; however, the indexes and indicators could only be tested against the occurrence of a real event. Therefore, the need exists to establish a sustainable and comprehensive evaluation system after important disasters to assess a country‘s performance, verify the indicators, and gain feedback on measurement systems and methodologies. There is diversity in emergency and preparedness for disasters in the four countries under study. The nature of the event (hurricanes, earthquakes, floods, and seismic activity), especially its frequency and the intensity of the damage experienced, is related to how each has designed its risk and disaster management policies and programs to face natural disasters. Vulnerabilities to disaster risks have been increasing, among other factors, because of uncontrolled urbanization, demographic density and poverty increase, social and economic marginalization, and lack of building code enforcement. The four countries under study have shown improvements in risk management capabilities, yet they are far from being completed prepared. Barbados‘ risk management performance is superior, in comparison, to the majority of the countries of the region. However, is still far in achieving high performance levels and sustainability in risk management, primarily when it has the highest gap between potential macroeconomic and financial losses and the ability to face them. The Dominican Republic has shown steady risk performance up to 2008, but two remaining areas for improvement are hazard monitoring and early warning systems. Jamaica has made uneven advances between 1990 and 2008, requiring significant improvements to achieve high performance levels and sustainability in risk management, as well as macroeconomic mitigation infrastructure. Trinidad and Tobago has the lowest risk management score of the 15 countries in the Latin American and Caribbean region as assessed by the IADB study in 2010, yet it has experienced an important vulnerability reduction. In sum, the results confirmed the high disaster risk management disparity in the Caribbean region.