Bayesian classification theory

The task of inferring a set of classes and class descriptions most likely to explain a given data set can be placed on a firm theoretical foundation using Bayesian statistics. Within this framework and using various mathematical and algorithmic approximations, the AutoClass system searches for the most probable classifications, automatically choosing the number of classes and complexity of class descriptions. A simpler version of AutoClass has been applied to many large real data sets, has discovered new independently-verified phenomena, and has been released as a robust software package. Recent extensions allow attributes to be selectively correlated within particular classes, and allow classes to inherit or share model parameters though a class hierarchy. We summarize the mathematical foundations of AutoClass

Autoclass: An automatic classification system

The task of inferring a set of classes and class descriptions most likely to explain a given data set can be placed on a firm theoretical foundation using Bayesian statistics. Within this framework, and using various mathematical and algorithmic approximations, the AutoClass System searches for the most probable classifications, automatically choosing the number of classes and complexity of class descriptions. A simpler version of AutoClass has been applied to many large real data sets, has discovered new independently-verified phenomena, and has been released as a robust software package. Recent extensions allow attributes to be selectively correlated within particular classes, and allow classes to inherit, or share, model parameters through a class hierarchy. The mathematical foundations of AutoClass are summarized

The senate majority party manipulates the way that budgets are brought to the floor, in order to protect its own members

Last year, the U.S. government shut down, and its debt ceiling was very nearly reached because of budget gridlock in Congress. When a budget agreement came, it was in the form of an ‘omnibus’ spending bill, which covered what would have otherwise been a number of appropriations bills. In new research, Peter Hanson finds that over the past 40 years, the Senate majority party has been able to exercise its power and shift towards this type of omnibus legislation in order to limit its exposure to difficult votes and ease the passage of the budget

Cory Gardner’s victory may be a sign that social conservatism is on the ebb in Colorado

This week, Republican Cory Gardner defeated incumbent Colorado Senator, Mark Udall, winning by three points after a tight election race. Peter Hanson writes that in the lead up to the election Gardner moved to the middle, disavowing support for a state personhood amendment, and remaining silent on marijuana legalization and same sex marriage. This break from the past, and Gardner’s subsequent victory, show that Colorado is now turning its back on social conservatism

PROJECT FOR THE ANALYSIS OF LAND TENURE AND AGRICULTURAL PRODUCTIVITY IN THE REPUBLIC OF MACEDONIA

The paper arises out of the Land Market Project and covers detailed data at the individual farm level and in-depth analyses of legal and historical processes. The agricultural sector in Macedonia is characterized by two very different farm enterprise types: small family farms operating on privately owned land, and large socially owned farms. About 30 percent of the total arable land in Macedonia belongs to socially owned farms. Most of the balance belong to the private farm sector; the cooperative sector occupies a small percentage of the arable land. The Land Markets Project addressed five tasks during the six-month term of the project: (1) assess the appropriateness of legislation, regulations, and institutions affecting land tenure and land use, (2) document and assess the land-related constraints to increased productivity and profitability of private farms, (3) document and assess the land-related constraints to increased productivity and profitability of socially owned farms, (4) propose land policy adjustments that would promote increased productivity and profitability of the agricultural sector, (5) identify financial and technical assistance to support the development of land markets that promote efficient, sustainable, and equitable increases in agricultural incomes. This paper reports the results of the first three tasks and then presents a comparative review of the land tenure and productivity results for both the private and the social sector. This comparison forms a basis for policy dialogue. The paper also includes a comprehensive discussion of the policy recommendations that stem from the Land Markets Project.Land tenure--Macedonia (Republic), Land use, Rural--Economic aspects--Macedonia (Republic), Farms, Size of--Macedonia (Republic), Agriculture--Economic aspects--Macedonia (Republic), Agricultural productivity--Macedonia (Republic), Land markets--Macedonia (Republic), Agrarian structure--Macedonia (Republic), Land Economics/Use, Productivity Analysis,

Romania's evolving legal framework for private sector development

As the economies of Central and Eastern Europe move from central planning and state ownership to market-driven development of private sector activity, they are undertaking comprehensive change in the"rules of the game", the legal framework for economic activity. The authors analyze the evolving legal framework for private sector development in Romania. The government has worked intensively in the last two years to create a legal framework for a market economy. It has adopted not only a new constitution but also extensive new legislation covering real and intellectual property, companies, and foreign investment. It has revived the pre-war civil code as a basis for contract law, and is moving to modernize its bankruptcy code. The only area surveyed in which little legal reform has occurred is antimonopoly law. Challenges remain in both law and practice. The broad principles of private ownership, free market exchange, and equal treatment of public and private firms are well recognized and have been largely achieved. But a tendency towards centralized, bureaucratic control remains in excessive requirements for approval and uneconomic limits on certain activities. Moreover, implementation will take a long time because there is little or no institutional framework for enforcement and dispute resolution. Developing a body of regulation and case practice will take time.Environmental Economics&Policies,National Governance,Legal Products,Banks&Banking Reform,Real&Intellectual Property Law

Thrifty Food Plan, 2006

The Thrifty Food Plan (TFP), a fundamental part of the U.S. food guidance system and the basis for maximum food stamp allotments, has been revised by USDA’s Center for Nutrition Policy and Promotion (CNPP), with assistance from USDA’s Food and Nutrition Service (FNS), Economic Research Service (ERS), and Agricultural Research Service (ARS). The TFP provides a representative healthful and minimal cost meal plan that shows how a nutritious diet may be achieved with limited resources. The Plan assumes that all purchased food is consumed at home. The TFP was last revised in 1999. The newly revised (2006) TFP differs from, and improves upon, the previous TFP in a number of ways. The 2006 TFP: • Is based on the 2005 Dietary Guidelines for Americans as well as the 2005 MyPyramid Food Guidance System. • Uses the prices low-income people paid for many foods. • Uses the latest data on food consumption, nutrient content, and food prices: the 2001- 2002 National Health and Nutrition Examination Survey and 2001-2002 Food Price Database. • Offers a more realistic reflection of the time available for food preparation, especially with increased expectations for work in assistance programs. Hence, it allows more prepared foods and requires somewhat fewer preparations from scratch. Although different from the previous TFP, the revised TFP is similar in one important respect: It is set at the same inflation-adjusted cost as the previous TFP. CNPP determined it was possible, for the 2001-2002 period, to obtain a healthful diet meeting current nutritional standards at a cost equal to the previous TFP’s cost.Thrifty Food Plan, USDA Food Plans, Diet Quality, Food Stamps, Cost of Food, Agricultural and Food Policy, Consumer/Household Economics, Demand and Price Analysis, Food Consumption/Nutrition/Food Safety, Food Security and Poverty,

DPpackage: Bayesian Semi- and Nonparametric Modeling in R

Data analysis sometimes requires the relaxation of parametric assumptions in order to gain modeling flexibility and robustness against mis-specification of the probability model. In the Bayesian context, this is accomplished by placing a prior distribution on a function space, such as the space of all probability distributions or the space of all regression functions. Unfortunately, posterior distributions ranging over function spaces are highly complex and hence sampling methods play a key role. This paper provides an introduction to a simple, yet comprehensive, set of programs for the implementation of some Bayesian nonparametric and semiparametric models in R, DPpackage. Currently, DPpackage includes models for marginal and conditional density estimation, receiver operating characteristic curve analysis, interval-censored data, binary regression data, item response data, longitudinal and clustered data using generalized linear mixed models, and regression data using generalized additive models. The package also contains functions to compute pseudo-Bayes factors for model comparison and for eliciting the precision parameter of the Dirichlet process prior, and a general purpose Metropolis sampling algorithm. To maximize computational efficiency, the actual sampling for each model is carried out using compiled C, C++ or Fortran code.

Behavior of new entries and developed tomato hybrids carrying Ty-2 gene

Tomato yellow leaf curl disease (TYLCD) is a serious problem hampering tomato production worldwide. In the Mediterranean Basin, disease incidence and severity are higher in the dry season increasing whitefly (Bemisia tabaci) populations. Effectiveness of resistance to Tomato yellow leaf curl virus (TYLCV) depends on both tomato host resistance and TYLCV complex species. So far, six different Ty tomato resistance genes have been identified. Two main TYLCV complex species, Tomato yellow leaf curl virus-Israel (TYLCV-Is) and Tomato yellow leaf curl Sardinia virus (TYLCSV), have been identified in Tunisia. The present work aimed to evaluate entries heterozygous for Ty-2 gene to help predict hybrid performance. Two tomato entries homozygous for the Ty-2 TYLCV resistance gene, one tomato hybrid homozygous for Ty-2 and two heterozygous hybrids were included, besides two susceptible tomato entries. Resistance response to TYLCD was recorded based on disease incidence and severity levels. Data analysis was performed according to presence/absence of Ty-2 gene and taking into account homozygosity and heterozygosity of Ty-2. Generalized linear model analysis was applied to check significance of individual factors' effects (i.e. effect of tomato entries or tomato groups of entries based on presence or absence of homozygous/heterozygous Ty-2 gene, block unit within the field trial and the year of the trial) on the dependent variables (disease incidence and severity). Further multi-comparison tests gave evidence on significant effect of Ty-2 homozygous gene tomato entries on TYLCD incidence and severity levels. The results were discussed with special focus on the relevance use of heterozygous hybrid tomato varieties