3,448 research outputs found
AGRICULTURAL COOPERATIVES AND RISK MANAGEMENT:IMPACT ON FINANCIAL PERFORMANCE
Agricultural cooperatives, like all agribusinesses, operate in an inherently risky environment. Many risk management tools exist, but agricultural cooperatives have been slow to adopt sophisticated risk management practices. Using simulation methods, this paper presents insight into how both traditional and innovative risk management practices effect the distribution of key financial variables for agricultural cooperatives.Agribusiness,
RISK MANAGEMENT TECHNIQUES FOR AGRICULTURAL COOPERATIVES: AN EMPIRICAL EVALUATION
While not ignoring risk, agricultural cooperatives tend to accommodate risk through the holding of internal capital reserves rather than engage in active risk management. A lack of information regarding the risk, returns, and the effect on cooperative financial performance of both traditional and innovative risk management strategies is likely a constraint to the adoption of active risk management by cooperatives. In this research, we examine the influence of alternative risk management strategies on cooperative financial performance, namely the return on assets (ROA) of grain merchandising cooperatives of various sizes. Strategies include traditional exchange traded futures and options strategies, an over-the-counter revenue swap, throughput insurance, and combinations of price and throughput strategies. Each of these strategies, for small, medium, and large size firms, are evaluated using a range of procedures including techniques which rely on mean-variance efficiency as well as evaluation procedures which help determine the ability of a strategy to mitigate downside risk. The results of the simulation exercise provide considerable support for the routine buying of at-the-money put options in setting a commodity floor price. The results also support the use, and perhaps the development, of insurance on cooperative throughput if the insurance product is used in conjunction with a price risk management strategy, in essence providing a hedge against downfalls in revenue. Over-the-counter revenue swaps, while intuitively appealing, did not perform well on average relative to more traditional exchange traded products. This result is especially important given the added counter party risk associated with such contracts. However, in some cases, the revenue swap, as well routine hedging with futures, performed better under a Value-at-Risk evaluation criteria than with a mean-variance criteria. Hence, it is important for cooperative managers to consider these results in the context of the risk management goals.Agribusiness,
The Bitsy Spacecraft Kernel: Reducing Nanosatellite Mission Cost in the MSFC Future-X Program through Miniaturized Technologies
A team led by AeroAstro Incorporated was selected under the Future-X program to fly an experiment in late 2000 to demonstrate key elements of reducing space mission cost utilizing Bitsy™ Spacecraft Kernel technology. The Small Payload Access to Space Experiment (SPASE) is funded through the Future-X program, and is to be launched in late 2000 using the Space Shuttle. The mission will also carry a small microgravity payload. The entire first mission, including space and ground systems and launch interfaces, will cost under 1M. Achieving on-orbit science missions with a cost comparable or below that of suborbital flights is made possible by: 1. Creation of a standardized core of spacecraft capabilities, not a standard bus, based on commercial-off-the-shelf (COTS) technologies, which the science team uses to manage spacecraft functions (patent pending); 2. Miniaturization, which both reduces recurring costs (fabrication and parts) and makes a minimal demand on launch vehicle services with very high reliability. The spacecraft “kernel”, as opposed to bus, does not have a traditional division into discrete subsystems, but rather manages power, thermal control, ACDS, C&DH, and communications in a package of a few kilograms. Its small size, light weight, and unique extensible architecture enables a variety of customizations to be added as needed to greatly expand the range of achievable missions. These added capabilities include modest in-space propulsion, which enables missions including those requiring large V for spacecraft inspection, orbit initialization or station keeping, or achieving unusual or energetic orbits without requiring very expensive launch capability. While Bitsy™ technology enables flying significant science, communications, and remote sensing missions with total mass of 10-60 kg forcosts similar to suborbital flights, there is in principle no limit to the size or complexity of payloads it can accommodate. The spacecraft program currently underway will demonstrate the capabilities provided by the combination of miniaturization and nanospacecraft architectures. It will perform a flight demonstration of the spacecraft, ground station, and flight operations control software offering standard interfaces to payloads and to launch systems, to be launched in late 2000 on the Shuttle Hitchhiker accommodation. The Bitsy™ kernel concept, progress to date on the SPASE mission, and the fundamental design and architecture decisions for each will be discussed in this paper
The Small Payload Access to Space Experiment (SPASE): Using Non-Traditional Aerospace Technology to Enable a New Generation of Low-Cost Missions
Launching on STS-108 Endeavour in late 2001, the Small Payload Access to Space Experiment (SPASE) demonstrates a number of new technologies, efficient ways to conduct a nanospacecraft development program, and how to take such a spacecraft through the Shuttle Hitchhiker safety and integration process. This paper describes the essential “lessons learned” in each of these areas. Commercial solar panels, batteries, imagers, photocells, integrated circuits, and manufacturing techniques are used throughout the vehicle, bringing the low cost and high manufacturing reliability of these products into the space realm. Core personnel carried the program from conception through proposal, requirements definition, design, development, integration, test, and delivery, making the whole program significantly more efficient. Shuttle safety issues were addressed from the beginning and continually throughout the program, as part of (not added to) the development effort. The information learned throughout this process, and the new doors opened by this demonstration – such as the first use of Lithium-Ion batteries in a Shuttle payload – help make space utilization more efficient, more affordable, and easier for future missions. AeroAstro’s Bitsy nanospacecraft kernel will be flight-proven by the SPASE mission
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Oxygen isotopic and petrological constraints on the origin and relationship of IIE iron meteorites and H chondrites
New oxygen isotopic measurements of IIEs and H chondrites are indistinguishable — strengthening a possible common origin for these groups. Combining oxygen results with mineralogy, the nature of their parent body or bodies can be explored
Using Creativity from Art and Engineering to Engage Students in Science
STEAM education, referring to integrated Science, Technology, Engineering, Art, and Mathematics, is a contemporary buzzword that is popular in many schools. In particular, many elementary school teachers who have been tasked to incorporate STEM teaching, because of the requirements of the Next Generation Science Standards, attempt to apply the arts in their science curriculum because they feel more comfortable using instructional approaches that incorporate creative activities such as crafts, drawing, and model construction than the core practices of STEM disciplines. Teachers can use the creative arts activities in two ways to enhance the STEM learning environment: 1) Using creative processes as a way to gain access to students’ ideas before science content is taught, to help guide further instruction; and 2) Using creativity as a means for students to express their understanding of science content. In this editorial, we explore how the arts can help students generate “Big Ideas” about science, construct questions, and share their understanding of the topic with authentic audiences. We will also discuss the scope and nature of discipline of specific STEM fields and how the arts could be incorporated into these practices
A review of Multi-Agent Simulation Models in Agriculture
Multi-Agent Simulation (MAS) models are intended to capture emergent properties of complex systems that are not amenable to equilibrium analysis. They are beginning to see some use for analysing agricultural systems. The paper reports on work in progress to create a MAS for specific sectors in New Zealand agriculture. One part of the paper focuses on options for modelling land and other resources such as water, labour and capital in this model, as well as markets for exchanging resources and commodities. A second part considers options for modelling agent heterogeneity, especially risk preferences of farmers, and the impacts on decision-making. The final section outlines the MAS that the authors will be constructing over the next few years and the types of research questions that the model will help investigate.multi-agent simulation models, modelling, agent-based model, cellular automata, decision-making, Crop Production/Industries, Environmental Economics and Policy, Farm Management, Land Economics/Use, Livestock Production/Industries,
MORTALITY IN THE MEDICARE POPULATION AND CHRONIC EXPOSURE TO FINE PARTICULATE AIR POLLUTION
Prospective cohort studies have provided evidence on longer-term mortality risks of fine particulate matter (PM2.5), but due to their complexity and costs, only a few have been conducted.
By linking monitoring data to the U.S. Medicare system by county of residence, we developed a retrospective cohort study, the Medicare Air Pollution Cohort Study (MCAPS), comprising over 20 million enrollees in the 250 largest counties during 2000-2002. We estimated log-linear regression models having as outcome the age-specific mortality rate for each county and as the main predictor, the average level for the study period 2000. Area-level covariates were used to adjust for socio-economic status and smoking. We reported results under several degrees of adjustment for spatial confounding and with stratification into by eastern, central and western counties.
We estimated that a 10 µg/m3 increase in PM25 is associated with a 7.6% increase in mortality (95% CI: 4.4 to 10.8%). We found a stronger association in the eastern counties than nationally, with no evidence of an association in western counties. When adjusted for spatial confounding, the estimated log-relative risks drop by 50%. We demonstrated the feasibility of using Medicare data to establish cohorts for follow-up for effects of air pollution.
Particulate matter (PM) air pollution is a global public health problem (1). In developing countries, levels of airborne particles still reach concentrations at which serious health consequences are well-documented; in developed countries, recent epidemiologic evidence shows continued adverse effects, even though particle levels have declined in the last two decades (2-6). Increased mortality associated with higher levels of PM air pollution has been of particular concern, giving an imperative for stronger protective regulations (7).
Evidence on PM and health comes from studies of acute and chronic adverse effects (6). The London Fog of 1952 provides dramatic evidence of the unacceptable short-term risk of extremely high levels of PM air pollution (8-10); multi-site time-series studies of daily mortality show that far lower levels of particles are still associated with short-term risk (5)(11-13). Cohort studies provide complementary evidence on the longer-term risks of PM air pollution, indicating the extent to which exposure reduces life expectancy. The design of these studies involves follow-up of cohorts for mortality over periods of years to decades and an assessment of mortality risk in association with estimated long-term exposure to air pollution (2-4;14-17). Because of the complexity and costs of such studies, only a small number have been conducted. The most rigorously executed, including the Harvard Six Cities Study and the American Cancer Society’s (ACS) Cancer Prevention Study II, have provided generally consistent evidence for an association of long- term exposure to particulate matter air pollution with increased all-cause and cardio-respiratory mortality (2,4,14,15). Results from these studies have been used in risk assessments conducted for setting the U.S. National Ambient Air Quality Standard (NAAQS) for PM and for estimating the global burden of disease attributable to air pollution (18,19).
Additional prospective cohort studies are necessary, however, to confirm associations between long-term exposure to PM and mortality, to broaden the populations studied, and to refine estimates by regions across which particle composition varies. Toward this end, we have used data from the U.S. Medicare system, which covers nearly all persons 65 years of age and older in the United States. We linked Medicare mortality data to (particulate matter less than 2.5 µm in aerodynamic diameter) air pollution monitoring data to create a new retrospective cohort study, the Medicare Air Pollution Cohort Study (MCAPS), consisting of 20 million persons from 250 counties and representing about 50% of the US population of elderly living in urban settings. In this paper, we report on the relationship between longer-term exposure to PM2.5 and mortality risk over the period 2000 to 2002 in the MCAPS
Digital signal processor software for the high-energy transient experiment satellite : video data filtering and storage
Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1994.by Scott Anthony Aquinas McDermott.M.Eng
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