System call interface for Asbestos labels

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2005.Includes bibliographical references (p. 53-55).Acetone is a secure operating system kernel that uses a shared address space and supports Asbestos labels. Acetone uses Asbestos labels to enable a wide variety of security policies including ones that prevent untrusted applications from being able to disclose private data. All threads run in the same address space, but have different memory access privileges. Acetone uses standard memory protection mechanisms to ensure that all memory accesses are consistent with label rules. The performance results show that these checks have a relatively low cost.by Clifford A. Frey.M.Eng

The Relationship of Peer Group Experiences to the Social Development of Boys at the Beginning of Adolescence

One of the most potent influences during the adolescent years is the power of group approval. The youth becomes subject to the conventions of his age group. By discovering the effect of various peer group experiences on the adolescent, schools and other character development agencies can better understand and guide the behavior of adolescents into socially responsible directions

Stigma: A Social, Cultural, and Moral Process

Anthropolog

Willingness to Pay: Referendum Contingent Valuation and Uncertain Project Benefits

This study uses contingent valuation (CV) methods to estimate the benefit of an environmental water quality project of the Tietê River and its tributaries that flow through the São Paulo, Brazil, Metropolitan Area (SPMA). This paper demonstrates the range alternative central tendency measures for WTP produced under alternative parametric and nonparametric approaches using data gathered from a recent referendum CV survey that was conducted in Brazil to analyze a large, multi-phase water quality improvement project. It explains why one of the most commonly used measures, the unrestricted mean of the conditional inverse distribution function of WTP, may be less desirable and more computationally intensive than simpler alternatives like the nonparametric mean of the marginal inverse distribution function.Water management, Economics, contingent valuation, econometric models, environmental impact analysis, economic development projects

Determinants of the Tournaments

No abstract provided in this article

The complexity of Free-Flood-It on 2xn boards

We consider the complexity of problems related to the combinatorial game Free-Flood-It, in which players aim to make a coloured graph monochromatic with the minimum possible number of flooding operations. Our main result is that computing the length of an optimal sequence is fixed parameter tractable (with the number of colours present as a parameter) when restricted to rectangular 2xn boards. We also show that, when the number of colours is unbounded, the problem remains NP-hard on such boards. This resolves a question of Clifford, Jalsenius, Montanaro and Sach (2010)

Research on plant disease and pest management is essential to sustainable agriculture

In the United States, a country with food in great abundance, it is difficult to realize that, were it not for the current level of plant disease and pest management, most human resources would be needed to obtain enough food and other plant and animal products merely to survive. Instead, there are surpluses, markets for many agricultural products are depressed, and funds available for research on plant disease and pest management-and for agricultural research generally-have plateaued or are declining. Why does the United States need more research on plant disease and pest management? Because the health and productivity of the crops and cropping systems upon which the people depend for their own consumption and for export cannot be sustained without continuing research and development. This continued investment is needed to manage ever threatening, changing, and rebounding diseases and pest populations. Moreover, disease and pest management of the future must be improved while simultaneously reducing our dependence on pesticides as one of many steps toward the goal of sustainable agriculture. The goal of plant disease and pest management is to ensure that crops are healthy enough to yield to their full genetic potential within the physical limits imposed by the uncontrolled variables of climate, weather, and soils. Management is defined as limiting damage from diseases or pests to a level at or below an acceptable economic or aesthetic threshold. This process does not require total elimination or eradication of the pest or disease problem

Research on plant disease and pest management is essential to sustainable agriculture

In the United States, a country with food in great abundance, it is difficult to realize that, were it not for the current level of plant disease and pest management, most human resources would be needed to obtain enough food and other plant and animal products merely to survive. Instead, there are surpluses, markets for many agricultural products are depressed, and funds available for research on plant disease and pest management-and for agricultural research generally-have plateaud or are declining. Why does the United States need more research on plant disease and pest management? Because the health and productivity of the crops and cropping systems upon which the people depend for their own consumption and for export cannot be sustained without continuing research and development. This continued investment is needed to manage ever threatening, changing, and rebounding diseases and pest populations. Moreover, disease and pest management of the future must be improved while simultaneously reducing our dependence on pesticides as one of many steps toward the goal of sustainable agriculture. The goal of plant disease and pest management is to ensure that crops are healthy enough to yield to their full genetic potential within the physical limits imposed by the uncontrolled variables of climate, weather, and soils. Management is defined as limiting damage from diseases or pests to a level at or below an acceptable economic or aesthetic threshold. This process does not require total elimination or eradication of the pest or disease problem. Reducing the use of pesticides is a desirable goal, but it depends on continued and increased investments in research on alternatives. For many chemical pesticides, the alternatives either are not yet developed or are less effective than chemicals. This research must be broadly based across the biological, physical, and social sciences. Moreover, the United States and the world depend not only on sustainable agriculture but also on sustainable growth in agriculture to meet a long-term increase in demand for quality and quantity of agricultural products expected from increases in both numbers and economic status of people (Rutan 1992). Furthermore. these increases must \u27be attained at the same time that available agricultural land is decreasing to satisfy other needs such as more land for recreation and urbanization; restoration of some wetlands, grasslands, and woodlands; and diversions of land from farming to other uses. Improved disease and pest management offers one of the few effective means by which the necessary increases in crop productivity can be accomplished while natural resources, including the remaining forests, are protected. These same principles apply to other uses of plants as well, including as ornamentals, for landscapes, and in parks and golf courses