The Impact of the 2005 Collective Bargaining Agreement on Competitive Balance in the National Hockey League

After a lockout that canceled the 2004‐05 season in the National Hockey League (NHL), the owners and players reached a collective bargaining agreement (CBA) that instituted a ‘hard’ salary cap, a modified revenue sharing system, and changes in free agency. The principal motivation for the new agreement was to raise competitiveness among the teams, in order to generate greater revenue and profitability and to support higher player salaries. The purpose of this study is to evaluate the impact of the CBA on competitive balance within the NHL and identify the principal determinants of the changes in competitiveness among the teams. We evaluate several alternative measures of competitive balance: dispersion in point percentage; the Herfindahl‐Hirschman index; the Gini Index; number of playoff games; and number of times a team has made the playoffs. We then develop and estimate alternative models of the determinants of point percentage (equal to points earned by a team divided by total possible points), in which point percentage is hypothesized to be a function of team payroll (a proxy for player talent) and free agent signings. We estimate the models using a sample of all 30 teams in the NHL across eleven seasons, including five seasons prior to the 2005 CBA (2000‐2004) and six seasons after its implementation (2006‐2011). We find that the new CBA has increased competitive balance, primarily because of a reduced impact of team payroll on point percentage and the facilitation of free agent signings which have more nearly equalized the talent across teams

Effect of Thickness Variation on Warp in High-Temperature Drying Plantation-Grown Loblolly Pine 2 by 4'S

Currently, an increasing proportion of southern pine dimension lumber comes from plantations; therefore, an increase in grade, value, and volume loss from warp is expected. One factor that has not been fully explored is the effect of lumber thickness variation on warp. The primary objective of this study was to increase quantitative understanding of the effects of thickness variation on crook, bow, and twist during high-temperature kiln-drying of plantation-grown loblolly pine to determine the importance of its control on the development of warp. Plantation-grown, 2 by 4 (nominal 50- by 100-mm) loblolly pine were kiln-dried at high temperature after surfacing them in such a way as to produce certain patterns of thickness variation. One group was not surfaced, i.e., left as mill run. All boards in a second group were surfaced to the same thickness. In a third group, the boards were divided into thirds, and each third surfaced to a different thickness. In this group, boards of the same thickness were stacked in vertical alignment to exaggerate the effect of the thickness variation. The fourth group differed from the third group in that the three thicknesses were randomly placed in the package. The extreme thickness variations did aggravate warp, especially twist. As a result of better sticker contact, thick boards warped less than did thin boards. However, even with perfect sticker contact, a substantial amount of warp developed, indicating that control of thickness variation can reduce but will not eliminate warp. Correlation of warp with board characteristics suggests that boards containing pith warp more than ones without pith, and boards sawn from near the center of the tree warp more than boards farther from the center of the tree

Pollination Ecology in the Southwest

Comparisons of the pollination biology of members of a number of genera (Prosopis, Helianthus, Opuntia, and Krameria) widespread in the arid American Southwest are made between sites in the Sonoran Desert of southern Arizona and the dry oak-juniper grasslands of central Texas. As in the majority of cases studied to date in the dry regions of the Southwest, solitary bees are the dominant pollinators in all of the systems examined. Rich arrays of oligolectic bees are associated with Prosopis, Helianthus, and Opuntia, but none with Krameria which offers oils rather than pollen and nectar as the primary floral reward. Nevertheless, Krameria appears to have the most restricted pollination system as none of the other taxa are obligately dependent on their specialist bees. Reward production and bee foraging activity were examined in Opuntia and Helianthus. In Helianthus, bimodal pollen presentation, but near constant nectar production, results in different activity patterns of the specialist and generalist bees visiting the flowers. Reward production is unimodal in the Opuntia species studied, but diurnal phenological differences can result in apparent partitioning of floral resources by foraging bees

Historical Arctic Logbooks Provide Insights into Past Diets and Climatic Responses of Cod

Gadus morhua (Atlantic cod) stocks in the Barents Sea are currently at levels not seen since the 1950s. Causes for the population increase last century, and understanding of whether such large numbers will be maintained in the future, are unclear. To explore this, we digitised and interrogated historical cod catch and diet datasets from the Barents Sea. Seventeen years of catch data and 12 years of prey data spanning 1930–1959 cover unexplored spatial and temporal ranges, and importantly capture the end of a previous warm period, when temperatures were similar to those currently being experienced. This study aimed to evaluate cod catch per unit effort and prey frequency in relation to spatial, temporal and environmental variables. There was substantial spatio-temporal heterogeneity in catches through the time series. The highest catches were generally in the 1930s and 1940s, although at some localities more cod were recorded late in the 1950s. Generalized Additive Models showed that environmental, spatial and temporal variables are all valuable descriptors of cod catches, with the highest occurring from 15–45°E longitude and 73–77°N latitude, at bottom temperatures between 2 and 4°C and at depths between 150 and 250 m. Cod diets were highly variable during the study period, with frequent changes in the relative frequencies of different prey species, particularly Mallotus villosus (capelin). Environmental variables were particularly good at describing the importance of capelin and Clupea harengus (herring) in the diet. These new analyses support existing knowledge about how the ecology of the region is controlled by climatic variability. When viewed in combination with more recent data, these historical relationships will be valuable in forecasting the future of Barents Sea fisheries, and in understanding how environments and ecosystems may respond

Systems for multivariate monitoring of behavioral status over time

Decision-theoretic criteria are presented for optimizing the information gathered from a series of interviews over time. It is shown that the optimum interviewing strategy depends strongly on assumptions about the covariation of behavior over time. Standard interviewing strategies, including the major-problem/target-complaints approach, are optimal only under extreme assumptions about behavior. An interviewing strategy based on dynamic programming is presented that will provide optimal information return from a series of interviews under assumptions that are realistic for mental health applications. A system using this approach can tailor its interviewing strategy to adapt to differences in interview content, item importance, and individual response patterns, selecting the optimally informative questions to ask each subject at each point in time. Simulation results show that this approach achieves a 34% reduction in the false negatives obtained with the major-problem/target-complaints method, and, depending on the acceptable error rate, a reduction of 47 % or more in the questions that are needed in standard interviewing

The detection and photometric redshift determination of distant galaxies using SIRTF's Infrared Array Camera

We investigate the ability of the Space Infrared Telescope Facility's Infrared Array Camera to detect distant (z ~ 3)galaxies and measure their photometric redshifts. Our analysis shows that changing the original long wavelength filter specifications provides significant improvements in performance in this and other areas.Comment: 28 pages incl 12 figures; to appear in June 1999 PASP. Fig.12 replaced with corrected versio

Mutation of Arabidopsis SPLICEOSOMAL TIMEKEEPER LOCUS1 Causes Circadian Clock Defects

The circadian clock plays a crucial role in coordinating plant metabolic and physiological functions with predictable environmental variables, such as dusk and dawn, while also modulating responses to biotic and abiotic challenges. Much of the initial characterization of the circadian system has focused on transcriptional initiation, but it is now apparent that considerable regulation is exerted after this key regulatory step. Transcript processing, protein stability, and cofactor availability have all been reported to influence circadian rhythms in a variety of species. We used a genetic screen to identify a mutation within a putative RNA binding protein (SPLICEOSOMAL TIMEKEEPER LOCUS1 [STIPL1]) that induces a long circadian period phenotype under constant conditions. STIPL1 is a homolog of the spliceosomal proteins TFP11 (Homo sapiens) and Ntr1p (Saccharomyces cerevisiae) involved in spliceosome disassembly. Analysis of general and alternative splicing using a high-resolution RT-PCR system revealed that mutation of this protein causes less efficient splicing of most but not all of the introns analyzed. In particular, the altered accumulation of circadian-associated transcripts may contribute to the observed mutant phenotype. Interestingly, mutation of a close homolog of STIPL1, STIP-LIKE2, does not cause a circadian phenotype, which suggests divergence in function between these family members. Our work highlights the importance of posttranscriptional control within the clock mechanism. © 2012 American Society of Plant Biologists. All rights reserved

Discussion of "Geodesic Monte Carlo on Embedded Manifolds"

Contributed discussion and rejoinder to "Geodesic Monte Carlo on Embedded Manifolds" (arXiv:1301.6064)Comment: Discussion of arXiv:1301.6064. To appear in the Scandinavian Journal of Statistics. 18 page