4,249 research outputs found

    Modelling the cost effectiveness of interferon beta and glatiramer acetate in the management of multiple sclerosis

    Get PDF
    OBJECTIVE: To evaluate the cost effectiveness of four disease modifying treatments (interferon betas and glatiramer acetate) for relapsing remitting and secondary progressive multiple sclerosis in the United Kingdom. DESIGN: Modelling cost effectiveness. SETTING: UK NHS. PARTICIPANTS: Patients with relapsing remitting multiple sclerosis and secondary progressive multiple sclerosis. MAIN OUTCOME MEASURES: Cost per quality adjusted life year gained. RESULTS: The base case cost per quality adjusted life year gained by using any of the four treatments ranged from £42 000 ($66 469; 61 630) to £98 000 based on efficacy information in the public domain. Uncertainty analysis suggests that the probability of any of these treatments having a cost effectiveness better than £20 000 at 20 years is below 20%. The key determinants of cost effectiveness were the time horizon, the progression of patients after stopping treatment, differential discount rates, and the price of the treatments. CONCLUSIONS: Cost effectiveness varied markedly between the interventions. Uncertainty around point estimates was substantial. This uncertainty could be reduced by conducting research on the true magnitude of the effect of these drugs, the progression of patients after stopping treatment, the costs of care, and the quality of life of the patients. Price was the key modifiable determinant of the cost effectiveness of these treatments

    Estimating population cardinal health state valuation models from individual ordinal (rank) health state preference data

    Get PDF
    Ranking exercises have routinely been used as warm-up exercises within health state valuation surveys. Very little use has been made of the information obtained in this process. Instead, research has focussed upon the analysis of health state valuation data obtained using the visual analogue scale, standard gamble and time trade off methods. Thurstone’s law of comparative judgement postulates a stable relationship between ordinal and cardinal preferences, based upon the information provided by pairwise choices. McFadden proposed that this relationship could be modelled by estimating conditional logistic regression models where alternatives had been ranked. In this paper we report the estimation of such models for the Health Utilities Index Mark 2 and the SF-6D. The results are compared to the conventional regression models estimated from standard gamble data, and to the observed mean standard gamble health state valuations. For both the HUI2 and the SF-6D, the models estimated using rank data are broadly comparable to the models estimated on standard gamble data and the predictive performance of these models is close to that of the standard gamble models. Our research indicates that rank data has the potential to provide useful insights into community health state preferences. However, important questions remain

    Estimating population cardinal health state valuation models from individual ordinal (rank) health state preference data

    Get PDF
    Ranking exercises have routinely been used as warm-up exercises within health state valuation surveys. Very little use has been made of the information obtained in this process. Instead, research has focussed upon the analysis of health state valuation data obtained using the visual analogue scale, standard gamble and time trade off methods. Thurstone’s law of comparative judgement postulates a stable relationship between ordinal and cardinal preferences, based upon the information provided by pairwise choices. McFadden proposed that this relationship could be modelled by estimating conditional logistic regression models where alternatives had been ranked. In this paper we report the estimation of such models for the Health Utilities Index Mark 2 and the SF-6D. The results are compared to the conventional regression models estimated from standard gamble data, and to the observed mean standard gamble health state valuations. For both the HUI2 and the SF-6D, the models estimated using rank data are broadly comparable to the models estimated on standard gamble data and the predictive performance of these models is close to that of the standard gamble models. Our research indicates that rank data has the potential to provide useful insights into community health state preferences. However, important questions remain.health state valuation; HUI-2; SF-6D

    Estimating population cardinal health state valuation models from individual ordinal (rank) health state preference data

    Get PDF
    Ranking exercises have routinely been used as warm-up exercises within health state valuation surveys. Very little use has been made of the information obtained in this process. Instead, research has focussed upon the analysis of health state valuation data obtained using the visual analogue scale, standard gamble and time trade off methods. Thurstone’s law of comparative judgement postulates a stable relationship between ordinal and cardinal preferences, based upon the information provided by pairwise choices. McFadden proposed that this relationship could be modelled by estimating conditional logistic regression models where alternatives had been ranked. In this paper we report the estimation of such models for the Health Utilities Index Mark 2 and the SF-6D. The results are compared to the conventional regression models estimated from standard gamble data, and to the observed mean standard gamble health state valuations. For both the HUI2 and the SF-6D, the models estimated using rank data are broadly comparable to the models estimated on standard gamble data and the predictive performance of these models is close to that of the standard gamble models. Our research indicates that rank data has the potential to provide useful insights into community health state preferences. However, important questions remain

    Determination of 3D Trajectories of Knots in Solar Prominences Using MSDP Data

    Get PDF
    In this paper we present a new method of restoration of the true thee-dimensional trajectories of the prominence knots based on ground-based observations taken with a single telescope, which is equipped with a Multi-Channel Subtractive Double Pass imaging spectrograph. Our method allows to evaluate true three-dimensional trajectories of the prominence knots without any assumptions concerning the shape of the trajectories or dynamics of the motion. The reconstructed trajectories of several knots observed in three prominences are presented.Comment: 14 pages, 9 figures, accepted for publication in Solar Physic

    Practical long-distance quantum key distribution system using decoy levels

    Get PDF
    Quantum key distribution (QKD) has the potential for widespread real-world applications. To date no secure long-distance experiment has demonstrated the truly practical operation needed to move QKD from the laboratory to the real world due largely to limitations in synchronization and poor detector performance. Here we report results obtained using a fully automated, robust QKD system based on the Bennett Brassard 1984 protocol (BB84) with low-noise superconducting nanowire single-photon detectors (SNSPDs) and decoy levels. Secret key is produced with unconditional security over a record 144.3 km of optical fibre, an increase of more than a factor of five compared to the previous record for unconditionally secure key generation in a practical QKD system.Comment: 9 page

    An investigation into the fertilizer potential of slaughterhouse cattle paunch

    Get PDF
    In Australia, the red meat processing industry actively seeks approaches to improve the management of solid waste from processing operations and enhance the environmental performance. Recycling of paunch waste to farmland could be a cost-effective and practicable environmental option. However, little is known about the agronomic value of fresh and composted paunch, and the associated requirements for land application. Therefore, a short-term experimental work was undertaken to assess potential risks due to weed seed contamination and determine the agronomic response of ryegrass (Lolium perenne L.) to soil incorporation of paunch. The risk of weed contamination from soil application of paunch appeared to be low; however, methods that account for viability of seeds may be required to fully discard such a risk. Soil application of paunch at field equivalent rates of 150-300 kg ha-1 of N increased dry matter yield by ≈30% on average compared with untreated grass, but was approximately 35% lower than a mineral fertilizer treatment applied at the same rates. Dry matter yield of paunch-treated grass was between 2000 and 3000 kg per ha over four consecutive cuts at 25-day intervals. Nitrogen use-efficiency of paunch was approximately 10% (range: 3% to 20%, depending on paunch type), and total N in harvested plant material showed values, which were between 2% and 3%. Overall, there appears to be potential for paunch-derived products to be used as a source of carbon and nutrients in crop production. Areas that merit a research priority within this space are also outlined in this paper. Such work is required to inform soil-, climate- and crop-specific land application rates, optimize agronomic performance, and minimize environmental concerns. There is also a requirement for the value proposition to industry to be determined, including reduced cost of disposal of material via gate fees and fertilizer replacement value

    Development Length Criteria: Bars Without Transverse Reinforcement

    Get PDF
    An expression that accurately represents development and splice strength as a function of concrete cover and bar spacing is developed and used to establish and evaluate modifications to the bond and development provisions of the ACI Building Code (ACI 318-89) for bars without transverse reinforcement The expression for development and splice strength is similar in form to expressions developed by Orangun, Jirsa, and Breen (1975, 1977), but is obtained using techniques that limit the effects of unintentional bias in the test data. The resulting expression provides a more accurate representation of development and splice strength than do the earlier expressions, and provides better guidance when there is a significant difference between the concrete cover and one-half of the clear spacing between bars. The expression for development and splice strength is used to establish new criteria that follow the format of ACI 318-89 and to evaluate design criteria that are currently under review by ACI Subcommittee 318-B. The new criteria that follow the format of ACI 318-89 are generally conservative and economical. The provisions under study by Subcommittee 318-B are unconservative for No. 6 bars and smaller with minimum covers and close spacings, and are overconservative for most bars with higher covers and wider spacings. Modifications are recommended that increase both the safety and the economy provided by the provisions under study by ACI Subcommittee 318-B

    Dryland ecohydrology and climate change: critical issues and technical advances

    Get PDF
    Drylands cover about 40% of the terrestrial land surface and account for approximately 40% of global net primary productivity. Water is fundamental to the biophysical processes that sustain ecosystem function and food production, particularly in drylands where a tight coupling exists between ecosystem productivity, surface energy balance, biogeochemical cycles, and water resource availability. Currently, drylands support at least 2 billion people and comprise both natural and managed ecosystems. In this synthesis, we identify some current critical issues in the understanding of dryland systems and discuss how arid and semiarid environments are responding to the changes in climate and land use. The issues range from societal aspects such as rapid population growth, the resulting food and water security, and development issues, to natural aspects such as ecohydrological consequences of bush encroachment and the causes of desertification. To improve current understanding and inform upon the needed research efforts to address these critical issues, we identify some recent technical advances in terms of monitoring dryland water dynamics, water budget and vegetation water use, with a focus on the use of stable isotopes and remote sensing. These technological advances provide new tools that assist in addressing critical issues in dryland ecohydrology under climate change
    corecore