2,195 research outputs found
NONCONSTANT PRICE EXPECTATIONS AND ACREAGE RESPONSE: THE CASE OF COTTON PRODUCTION IN GEORGIA
An adaptive regression model is used to examine the relative importance of cash and government support prices in determining cotton production over time. The results show that the cash price is more important as a source of price information for cotton producers than the government program price. The cash price was shown to have a greater influence on acreage response in every year, including periods thought to be dominated by government commodity programs.Adaptive regression, Cotton acreage response, Price expectations, Crop Production/Industries,
Cost effectiveness of ward based non-invasive ventilation for acute exacerbations of chronic obstructive pulmonary disease: economic analysis of randomised controlled trial
OBJECTIVE: To evaluate the cost effectiveness of standard treatment with and without the addition of ward based non-invasive ventilation in patients admitted to hospital with an acute exacerbation of chronic obstructive pulmonary disease. DESIGN: Incremental cost effectiveness analysis of a randomised controlled trial. SETTING: Medical wards in 14 hospitals in the United Kingdom. PARTICIPANTS: The trial comprised 236 patients admitted to hospital with an acute exacerbation of chronic obstructive pulmonary disease and mild to moderate acidosis (pH 7.25-7.35) secondary to respiratory failure. The economic analysis compared the costs of treatment that these patients received after randomisation. MAIN OUTCOME MEASURE: Incremental cost per in-hospital death. RESULTS: 24/118 died in the group receiving standard treatment and 12/118 in the group receiving non-invasive ventilation (P=0.05). Allocation to the group receiving non-invasive ventilation was associated with a reduction in costs of £49 362 ($78 741; 73 109), mainly through reduced use of intensive care units. The incremental cost effectiveness ratio was £645 per death avoided (95% confidence interval £2310 to £386), indicating a dominant (more effective and less costly) strategy. Modelling of these data indicates that a typical UK hospital providing a non-invasive ventilation service will avoid six deaths and three to nine admissions to intensive care units per year, with an associated cost reduction of £12 000-53 000 per year. CONCLUSIONS: Non-invasive ventilation is a highly cost effective treatment that both reduced total costs and improved mortality in hospital
Economics of smoking cessation
Smoking imposes a huge economic burden on society— currently up to 15% of total healthcare costs in developed countries. Smoking cessation can save years of life, at a very low cost compared with alternative interventions. This chapter reviews some of the economic aspects of smoking cessation
Radiation from a Charge Uniformly Accelerated for All Time
A recent paper of Singal [Gen. Rel. Grav. 27 (1995), 953-967] argues that a
uniformly accelerated particle does not radiate, in contradiction to the
consensus of the research literature over the past 30 years. This note points
out some questionable aspects of Singal's argument and shows how similar
calculations can lead to the opposite conclusion.Comment: LaTeX, 9 pages, to appear in General Relativity and Gravitatio
Genetic algorithms with elitism-based immigrants for changing optimization problems
Copyright @ Springer-Verlag Berlin Heidelberg 2007.Addressing dynamic optimization problems has been a challenging task for the genetic algorithm community. Over the years, several approaches have been developed into genetic algorithms to enhance their performance in dynamic environments. One major approach is to maintain the diversity of the population, e.g., via random immigrants. This paper proposes an elitism-based immigrants scheme for genetic algorithms in dynamic environments. In the scheme, the elite from previous generation is used as the base to create immigrants via mutation to replace the worst individuals in the current population. This way, the introduced immigrants are more adapted to the changing environment. This paper also proposes a hybrid scheme that combines the elitism-based immigrants scheme with traditional random immigrants scheme to deal with significant changes. The experimental results show that the proposed elitism-based and hybrid immigrants schemes efficiently improve the performance of genetic algorithms in dynamic environments
Trajectories for the 1976 - 1980 Grand Tour opportunities. Volume 3 - Trajectory data for alternate Grand Tour missions
Tabulating trajectory data for alternate Grand Tour missions from earth for period 1976 to 198
A distributed algorithm for European options with nonlinear volatility
A distributed algorithm is developed to solve nonlinear Black-Scholes equations in the hedging of portfolios. The algorithm is based on an approximate inverse Laplace transform and is particularly suitable for problems that do not require detailed knowledge of each intermediate time steps
Applications of graphics to support a testbed for autonomous space vehicle operations
Researchers describe their experience using graphics tools and utilities while building an application, AUTOPS, that uses a graphical Machintosh (TM)-like interface for the input and display of data, and animation graphics to enhance the presentation of results of autonomous space vehicle operations simulations. AUTOPS is a test bed for evaluating decisions for intelligent control systems for autonomous vehicles. Decisions made by an intelligent control system, e.g., a revised mission plan, might be displayed to the user in textual format or he can witness the effects of those decisions via out of window graphics animations. Although a textual description conveys essentials, a graphics animation conveys the replanning results in a more convincing way. Similarily, iconic and menu-driven screen interfaces provide the user with more meaningful options and displays. Presented here are experiences with the SunView and TAE Plus graphics tools used for interface design, and the Johnson Space Center Interactive Graphics Laboratory animation graphics tools used for generating out out of the window graphics
- …