47 research outputs found
Reducing the Effects of Unequal Number of Games on Rankings
Ranking is an important mathematical process in a variety of contexts such as information retrieval, sports and business. Sports ranking methods can be applied both in and beyond the context of athletics. In both settings, once the concept of a game has been defined, teams (or individuals) accumulate wins, losses, and ties, which are then factored into the ranking computation. Many settings involve an unequal number of games between competitors. This paper demonstrates how to adapt two sports rankings methods, the Colley and Massey ranking methods, to settings where an unequal number of games are played between the teams. In such settings, the standard derivations of the methods can produce nonsensical rankings. This paper introduces the idea of including a super-user into the rankings and considers the effect of this fictitious player on the ratings. We apply such techniques to rank batters and pitchers in Major League baseball, professional tennis players, and participants in a free online social game. The ideas introduced in this paper can further the scope that such methods are applied and the depth of insight they offer
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High-solids black liquor firing in pulp and paper industry kraft recovery boilers: Phase 1 -- Final report. Volume 2: Project technical results
This project is a multiple-phase effort to develop technologies to improve high-solids black liquor firing in pulp mill recovery boilers. The principal means to this end is to construct and operate a pilot-scale recovery furnace simulator (RFS) in which these technologies can be tested. The Phase 1 objectives are to prepare a preliminary design for the RFS, delineate a project concept for evaluating candidate technologies, establish industrial partners, and report the results. Phase 1 addressed the objectives with seven tasks: Develop a preliminary design of the RFS; estimate the detailed design and construction costs of the RFS and the balance of the project; identify interested parties in the paper industry and key suppliers; plan the Phase 2 and Phase 3 tests to characterize the RFS; evaluate the economic justification for high-solids firing deployment in the industry; evaluate high-solids black liquor property data to support the RFS design; manage the project and reporting results, which included planning the future program direction
Habitat Assessment of Non-Wadeable Rivers in Michigan
Habitat evaluation of wadeable streams based on accepted protocols provides a rapid and widely used adjunct to biological assessment. However, little effort has been devoted to habitat evaluation in non-wadeable rivers, where it is likely that protocols will differ and field logistics will be more challenging. We developed and tested a non-wadeable habitat index (NWHI) for rivers of Michigan, where non-wadeable rivers were defined as those of order â„5, drainage area â„1600 km 2 , mainstem lengths â„100 km, and mean annual discharge â„15 m 3 /s. This identified 22 candidate rivers that ranged in length from 103 to 825 km and in drainage area from 1620 to 16,860 km 2 . We measured 171 individual habitat variables over 2-km reaches at 35 locations on 14 rivers during 2000â2002, where mean wetted width was found to range from 32 to 185 m and mean thalweg depth from 0.8 to 8.3 m. We used correlation and principal components analysis to reduce the number of variables, and examined the spatial pattern of retained variables to exclude any that appeared to reflect spatial location rather than reach condition, resulting in 12 variables to be considered in the habitat index. The proposed NWHI included seven variables: riparian width, large woody debris, aquatic vegetation, bottom deposition, bank stability, thalweg substrate, and off-channel habitat. These variables were included because of their statistical association with independently derived measures of human disturbance in the riparian zone and the catchment, and because they are considered important in other habitat protocols or to the ecology of large rivers. Five variables were excluded because they were primarily related to river size rather than anthropogenic disturbance. This index correlated strongly with indices of disturbance based on the riparian (adjusted R 2 = 0.62) and the catchment (adjusted R 2 = 0.50), and distinguished the 35 river reaches into the categories of poor (2), fair (19), good (13), and excellent (1). Habitat variables retained in the NWHI differ from several used in wadeable streams, and place greater emphasis on known characteristic features of larger rivers.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41269/1/267_2004_Article_141.pd
When the Blood Hits Your Brain: The Neurotoxicity of Extravasated Blood
Hemorrhage in the central nervous system (CNS), including intracerebral hemorrhage (ICH), intraventricular hemorrhage (IVH), and aneurysmal subarachnoid hemorrhage (aSAH), remains highly morbid. Trials of medical management for these conditions over recent decades have been largely unsuccessful in improving outcome and reducing mortality. Beyond its role in creating mass effect, the presence of extravasated blood in patients with CNS hemorrhage is generally overlooked. Since trials of surgical intervention to remove CNS hemorrhage have been generally unsuccessful, the potent neurotoxicity of blood is generally viewed as a basic scientific curiosity rather than a clinically meaningful factor. In this review, we evaluate the direct role of blood as a neurotoxin and its subsequent clinical relevance. We first describe the molecular mechanisms of blood neurotoxicity. We then evaluate the clinical literature that directly relates to the evacuation of CNS hemorrhage. We posit that the efficacy of clot removal is a critical factor in outcome following surgical intervention. Future interventions for CNS hemorrhage should be guided by the principle that blood is exquisitely toxic to the brain
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High-solids black liquor firing in pulp and paper industry Kraft recovery boilers. Final report, Phase 1, Volume 1: Executive summary
This project is a multiple-phase effort to develop technologies to improve high-solids black liquor firing in pulp mill recovery boilers. The objectives are to develop a preliminary design of a recovery furnace simulator; evaluate the economics of high-solids; and delineate a project concept for evaluating candidate technologies to improve chemical recovery
Hip Fracture Mortality: Differences Between Intertrochanteric and Femoral Neck Fractures
The purpose of this study was to identify the specific risk factors that affect mortality in patients with hip fractures and differentiate mortality-associated factors between intertrochanteric (IT) and femoral neck (FN) fractures. A total of 1538 consecutive patients with hip fractures were treated at the authors\u27 institution between January 2005 and October 2013. Ultimately 858 IT and 479 FN fracture patients were included on the basis of age \u3e60 years with an isolated hip fracture. Mortality rate at 90 days was 12.1% for IT and 9.6% for FN fractures. In both IT and FN fractures, variables associated with mortality risk include increased age, greater days to surgery, male gender, decreased body mass index, and increased American Society of Anesthesiologists score. When evaluated independently, the presence of cardiac arrhythmia and chronic kidney disease was strongly associated with greater mortality risk in FN fracture patients. The presence of chronic kidney disease and hypertension correlated with decreased mortality risk among FN fracture patients. (Journal of Surgical Orthopaedic Advances 27(1):64-71, 2018)
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A Critical Assessment of the Golden Hour and the Impact of Procedural Timing in Stroke Thrombectomy
Previous studies in acute ischemic stroke have demonstrated the importance of minimizing delays to endovascular treatment and keeping thrombectomy procedural timesâat <30-60 minutes. The purpose of this study was to investigate the impact of thrombectomy procedural times on clinical outcomes.
We retrospectively compared 319 patients having undergone thrombectomy according to procedural time (60 minutes) and time from stroke onset to endovascular therapy (â€6 or >6âhours). Clinical characteristics of patients with postprocedural intracranial hemorrhage were also assessed. Logistic regression was used to determine independent predictors of poor outcome at 90 days (mRS â„3).
Greater age (OR, 1.03; 95% CI, 1.01-1.06;
=â.016), higher admission NIHSS score (OR, 1.10; 95% CI, 1.04-1.16;
=â.001), history of diabetes mellitus (OR, 1.96; 95% CI, 1.05-3.65;
=â.034), and postprocedural intracranial hemorrhage were independently associated with greater odds of poor outcome. Modified TICI scale scores of 2c (OR, 0.11; 95% CI, 0.04-0.28;
<â.001) and 3 (OR, 0.15; 95% CI, 0.06-0.38;
6âhours was independently associated with increased odds of poor outcome (OR, 2.20; 95% CI, 1.11-4.36;
=â.024) in the final multivariate model (area under the curve = 0.820). Procedural time was not independently associated with clinical outcome in the final multivariate model (
>â.05).
Thrombectomy procedural times beyond 60 minutes are associated with lower revascularization rates and worse 90-day outcomes. Procedural time itself was not an independent predictor of outcome. While stroke thrombectomy procedures should be performed rapidly, our study emphasizes the significance of achieving revascularization despite the requisite procedural time. However, the potential for revascularization must be weighed against the risks associated with multiple thrombectomy attempts