Pseudorandomness for Approximate Counting and Sampling

We study computational procedures that use both randomness and nondeterminism. The goal of this paper is to derandomize such procedures under the weakest possible assumptions. Our main technical contribution allows one to “boost” a given hardness assumption: We show that if there is a problem in EXP that cannot be computed by poly-size nondeterministic circuits then there is one which cannot be computed by poly-size circuits that make non-adaptive NP oracle queries. This in particular shows that the various assumptions used over the last few years by several authors to derandomize Arthur-Merlin games (i.e., show AM = NP) are in fact all equivalent. We also define two new primitives that we regard as the natural pseudorandom objects associated with approximate counting and sampling of NP-witnesses. We use the “boosting” theorem and hashing techniques to construct these primitives using an assumption that is no stronger than that used to derandomize AM. We observe that Cai's proof that S_2^P ⊆ PP⊆(NP) and the learning algorithm of Bshouty et al. can be seen as reductions to sampling that are not probabilistic. As a consequence they can be derandomized under an assumption which is weaker than the assumption that was previously known to suffice

EFFECTS OF FOOD ASSISTANCE AND NUTRITION PROGRAMS ON NUTRITION AND HEALTH: VOLUME 4, EXECUTIVE SUMMARY OF THE LITERATURE REVIEW

This report provides a summary of a comprehensive review and synthesis of published research on the impact of USDA's domestic food and nutrition assistance programs on participants' nutrition and health outcomes. The outcome measures reviewed include food expenditures, household nutrient availability, dietary intake, other measures of nutrition status, food security, birth outcomes, breastfeeding behaviors, immunization rates, use and cost of health care services, and selected nonhealth outcomes, such as academic achievement and school performance (children) and social isolation (elderly). The report is one of four volumes produced by a larger study that includes Volume 1, Research Design; Volume 2, Data Sources; Volume 3, Literature Review; and Volume 4, Executive Summary of the Literature Review. The review examines the research on 15 USDA food assistance and nutrition programs but tends to focus on the largest ones for which more research is available: food stamps, school feeding programs, and the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC). Over half of USDA's budget - $41.6 billion in fiscal year 2003 - was devoted to food assistance and nutrition programs that provide low-income families and children with access to a healthy diet.Dietary intake, food expenditures, nutrient availability, nutrient intake, nutritional status, nutrition and health outcomes, USDAs food assistance and nutrition programs, Food Security and Poverty,

EC Visa Facilitation and Readmission Agreements: Implementing a New EU Security Approach in the Neighbourhood

With the Eastern Enlargement successfully completed, the EU is searching for a proper balance between internal security and external stabilisation that is acceptable to all sides. This paper focuses on an EU foreign policy instrument that is a case in point for this struggle: EC visa facilitation and readmission agreements. By looking at the EU's strategy on visa facilitation and readmission, this paper aims to offer a first systematic analysis of the objectives, substance and political implications of these agreements as a means to implement a new EU security approach in the neighbourhood. In offering more relaxed travel conditions in exchange for the signing of an EC readmission agreement and reforming domestic justice and home affairs, the EU has found a new way to press for reforms in neighbouring countries while addressing a major source of discontent in these countries. The analysis concludes with the broader implications of these agreements and argues that even if the facilitated travel opportunities are beneficial for the citizens of the target countries, the positive achievements are undermined by the Schengen enlargement, which makes the new member states tie up their borders to those of their neighbours.EU, EC visa facilitation, readmission agreements, European Neighbourhood Policy, Stabilisation and Association Process, Justice and Home Affairs

Political Data for Applied Political Economy Research

The availability of appropriate empirical measures to represent political and institutional factors is a crucial issue in the applied political economy research. This paper is intended as a contribution to the collection and circulation of political data. Having been involved for quite a considerable time in projects on the empirical analysis of political economy models, I have in the end assembled a data-set for the group of western European countries that includes a variety (about 40) of indicators. Some of these indicators have been previously used in the literature, but others are innovative. The categories of variables in the data set are presented and two econometric applications discussed. The first application is an analysis of the determinants of government duration. Differently from most of the literature in this area, the specification of the statistical model is theory-based and not driven by an inductive approach. The second application is an analysis of the determinants of government spending decisions. Again, specific theoretical predictions are tested. The focus is on the role of the ideological (and numerical) fragmentation of the government. The data-set will be soon made available on the WWW and, for the time being, is available from the author upon request.political economy, data collection, government duration, government expenditure

Multivariate adaptive regression splines for estimating riverine constituent concentrations

Regression-based methods are commonly used for riverine constituent concentration/flux estimation, which is essential for guiding water quality protection practices and environmental decision making. This paper developed a multivariate adaptive regression splines model for estimating riverine constituent concentrations (MARS-EC). The process, interpretability and flexibility of the MARS-EC modelling approach, was demonstrated for total nitrogen in the Patuxent River, a major river input to Chesapeake Bay. Model accuracy and uncertainty of the MARS-EC approach was further analysed using nitrate plus nitrite datasets from eight tributary rivers to Chesapeake Bay. Results showed that the MARS-EC approach integrated the advantages of both parametric and nonparametric regression methods, and model accuracy was demonstrated to be superior to the traditionally used ESTIMATOR model. MARS-EC is flexible and allows consideration of auxiliary variables; the variables and interactions can be selected automatically. MARS-EC does not constrain concentration-predictor curves to be constant but rather is able to identify shifts in these curves from mathematical expressions and visual graphics. The MARS-EC approach provides an effective and complementary tool along with existing approaches for estimating riverine constituent concentrations

PERFECTIONISM AND PSYCHOLOGICAL FLEXIBILITY IN UNIVERSITY STUDENTS AND COUNSELING CLIENTS

ABSTRACT Psychological inflexibility and perfectionism have garnered a great deal of interest as having significant influence on mental health (e.g., Kashdan & Rottenberg, 2010; Curran & Hill, 2017). A number of researchers have examined the connection between perfectionism and psychological flexibility (e.g., Moroz & Dunkley, 2015; Santanello & Gardner, 2007) and suggested that processes involved in psychological flexibility may be important in understanding perfectionism. The current study was developed to further investigate the relationship between perfectionism and the processes of psychological flexibility and psychological inflexibility. The sample included 833 participants recruited from college and university counseling centers and university undergraduate courses, with 535 recruited from the undergraduate courses and 298 recruited from university counseling centers. Measurement invariance tests supported the two-factor structure of the Short Almost Perfect Scale and the Frost Multidimensional Perfectionism Scale – Brief, as well as the six-factor structure of psychological flexibility and psychological in flexibility of the Multidimensional Psychological Flexibility Inventory. The results of a Latent Profile Analyses (LPA) offered support for a four-class model of perfectionism based on factors derived from the two perfectionism measures. Auxiliary analyses revealed variable levels of psychological flexibility and inflexibility among perfectionism-related latent classes with adaptive perfectionism classes having higher levels of psychological flexibility and lower levels of psychological inflexibility than maladaptive perfectionism classes

EFFECTS OF FOOD ASSISTANCE AND NUTRITION PROGRAMS ON NUTRITION AND HEALTH: VOLUME 3, LITERATURE REVIEW

This report provides a comprehensive review and synthesis of published research on the impact of USDA's domestic food and nutrition assistance programs on participants' nutrition and health outcomes. The outcome measures reviewed include food expenditures, household nutrient availability, dietary intake, other measures of nutrition status, food security, birth outcomes, breastfeeding behaviors, immunization rates, use and cost of health care services, and selected nonhealth outcomes, such as academic achievement and school performance (children) and social isolation (elderly). The report is one of four volumes produced by a larger study that includes Volume 1, Research Design; Volume 2, Data Sources; Volume 3, Literature Review; and Volume 4, Executive Summary of the Literature Review. The review examines the research on 15 USDA food assistance programs but tends to focus on the largest ones for which more research is available: food stamps, school feeding programs, and the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC). Over half of USDA's budget - $41.6 billion in fiscal year 2003 - was devoted to food assistance and nutrition programs that provide low-income families and children with access to a healthy diet.Dietary intake, food expenditures, nutrient availability, nutrient intake, nutritional status, nutrition and health outcomes, USDA, Food Security and Poverty,