An empirical Bayes' procedure for ranking players in Ryder Cup golf

We describe a model to obtain strengths and rankings of players appearing in golf's Ryder Cup. Obtaining rankings is complicated because of two reasons. First, competitors do not compete on an equal number of occasions, with some competitors appearing too infrequently for their ranking to be estimated with any degree of certainty, and second, different competitors experience different levels of volatility in results. Our approach is to assume the competitor strengths are drawn from some common distribution. For small numbers of competitors, as is the case here, we fit the model using Monte-Carlo integration. Results suggest there is very little difference between the top performing players, though Scotland's Colin Montgomerie is estimated as the strongest Ryder Cup player.     

Case study for evaluating campus sustainability: nitrogen balance for the University of Minnesota

American ecologists recently began to address the ecology of cities. Concurrently, higher education institutions have developed sustainability education programs and instituted sustainability policies and projects. This paper draws together these two disparate areas by examining the nitrogen (N) budget of the Twin Cities campus of the University of Minnesota. We addressed the question: what were the annual inputs, outputs and internal cycles of N on the University of Minnesota Twin Cities campus? We found that 508 Mg N yr-1 were brought into the campus and 494 Mg N yr-1 were emitted from the University of Minnesota campus. The largest N inputs were abiotic fixation (conversion of N₂ to NO_x by combustion) and food for humans and animals. The largest N output was NO_x, followed by wastewater. Our results expand the understanding of the ecology of institutions within an urban area and provide an opportunity for improving urban ecology education and environmental policy at educational institutions.     

DEGENERACY AND THE (MIS)INTERPRETATION OF SENSITIVITY ANALYSIS IN LINEAR PROGRAMMING

Under conditions of degeneracy, sensitivity analysis information such as cost and right-hand-side ranges, which are produced by standard linear programming procedures used in commercial codes, can be misleading. From a managerial perspective, the interpretation of such information can be erroneous. In this paper we present these problems, explain their occurence with elementary examples, and discuss procedures for their resolution.     

Testing for space-time clusters of unknown size

The Knox test is widely used in epidemiology to test for infection or contagion, which is indicated by an excess of cases that are close both in space and time. Often, however, the values of the space and time critical parameters that define 'closeness' are unknown. An exact test is proposed for this situation, its computer implementation is described and examples of its use on published data sets are given. Other possible applications of the method adopted here are discussed. This is an example of a test where nuisance parameters are absent under H0, and where the distribution of the test statistic can be found numerically.     

Viability of Auction‐Based Revenue Management in Sequential Markets

The Internet is providing an opportunity to revenue management practitioners to exploit the potential of auctions as a new price distribution channel. We develop a stochastic model for a high‐level abstraction of a revenue management system (RMS) that allows us to understand the potential of incorporating auctions in revenue management in the presence of forecast errors associated with key parameters. Our abstraction is for an environment where two market segments book in sequence and revenue management approaches consider auctions in none, one, or both segments. Key insights from our robust results are (i) limited auctions are best employed closest to the final sale date, (ii) counterbalancing forecast errors associated with overall traffic intensity and the proportion of customer arrivals in a segment is more important if an auction is adopted in that segment, and (iii) it is critically important not to err on the side of overestimating market willingness to pay.     

Forward and backward, horizontal and vertical: Transformation of occupational credentialing in the schooled society

Underdeveloped theory about educational credentialing flies in the face of the immense practice of educational degree attainment by ever increasing proportions of each new generation, and the ensuing pervasive belief in the power of degrees to both allocate individuals in the labor market and to serve as job requirements throughout the occupational structure. Considering educational credentialing at the center of the educational revolution in postindustrial society, a new theoretical argument is developed from the premise that education as an institution provides the logic by which educational credentialing becomes evermore legitimate, more so than from forces outside the institution itself such as the economy and labor market demand. In support of the proposed theory of credentialing, multiple sets of new findings about education, occupations, and work show that the common negative notion of run-away educational credentialism does not fit empirical trends. Second, as a function of widely held beliefs about education in postindustrial society, four institutional processes by which educational credentialing has deeply integrated into the occupational structure are described and illustrated with empirical observations and analyses. Lastly, consequences of the rapid and robust educational transformation of occupational credentialing for future sociological inquiry into social stratification and mobility are discussed.     

Eighth‐Grade School Form and Resilience in the Transition to High School: A Comparison of Middle Schools and K‐8 Schools

We examine a set of academic and social outcomes in 9th grade, comparing middle school attendees with those who attended K‐8 schools. Previous research with these data has shown that there are few differences in 8th‐grade outcomes by school type. Here we extend these findings to determine whether school form influences student outcomes in the first year of high school. The results reveal several domains in which attendance at a middle school results in worse outcomes (e.g., greater rates of course failure); however, we find that a large portion of the difference by type of a student's 8th‐grade school is accounted for by differential rates of attendance at the district's magnet schools. That is, our results indicate that type of school attended during the middle grades is significantly and positively related to magnet school attendance and thereby on the academic outcomes in the 9th‐grade year.     

An overview of the Salmonella enteritidis risk assessment for shell eggs and egg products.

This article summarizes a quantitative microbial risk assessment designed to characterize the public health impact of consumption of shell eggs and egg products contaminated with Salmonella Enteritidis (SE). This risk assessment's objectives were to: (1) establish the baseline risk of foodborne illness from SE, (2) identify and evaluate potential risk mitigation strategies, and (3) identify data gaps related to future research efforts. The risk assessment model has five modules. The Egg Production module estimates the number of eggs produced that are SE-contaminated. Shell Egg Processing, Egg Products Processing, and Preparation & Consumption modules estimate the increase or decrease in the numbers of SE organisms in eggs or egg products as they pass through storage, transportation, processing, and preparation. A Public Health Outcomes module then calculates the incidence of illnesses and four clinical outcomes, as well as the cases of reactive arthritis associated with SE infection following consumption. The baseline model estimates an average production of 2.3 million SE-contaminated shell eggs/year of the estimated 69 billion produced annually and predicts an average of 661,633, human illnesses per year from consumption of these eggs. The model estimates approximately 94% of these cases recover without medical care, 5% visit a physician, an additional 0.5% are hospitalized, and 0.05% result in death. The contribution of SE from commercially pasteurized egg products was estimated to be negligible. Five mitigation scenarios were selected for comparison of their individual and combined effects on the number of human illnesses. Results suggest that mitigation in only one segment of the farm-to-table continuum will be less effective than several applied in different segments. Key data gaps and areas for future research include the epidemiology of SE on farms, the bacteriology of SE in eggs, human behavior in food handling and preparation, and human responses to SE exposure.