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

ICAR: endoscopic skull‐base surgery

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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 ≥5, drainage area ≥1600 km 2 , mainstem lengths ≥100 km, and mean annual discharge ≥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 2000–2002, 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

Preservation of olfaction after unilateral endoscopic approach for resection of esthesioneuroblastoma

Objectives We present a case of olfactory preservation after a unilateral transcribriform transethmoidal endoscopic resection of esthesioneuroblastoma. We also discuss the oncologic results of endoscopic and transcranial approaches and describe the potential benefits and limitations of an endoscopic approach. Setting Single academic medical center. Participant and Design The clinical course of a 28-year-old patient who underwent endoscopic en bloc resection of esthesioneuroblastoma through a unilateral transcribriform transethmoidal approach was reviewed. Results Imaging demonstrated a left-sided nasal mass with cribriform plate involvement (Kadish C). Intraoperatively, the left olfactory bulb and epithelium were sacrificed. Negative frozen sections were obtained from the right olfactory epithelium and dura surrounding the right olfactory bulb. Reconstruction was performed using a multilayered closure of fascia, rigid buttress, and nasoseptal flap. Histology was consistent with esthesioneuroblastoma. Postoperative clinical evaluation, endoscopy, and magnetic resonance imaging demonstrated no evidence of residual or recurrent tumor at 18 months. The UPSIT smell testing revealed normal olfaction preoperatively, moderate microsomia at 3 months postoperatively, and mild microsomia at 18 months postoperatively. Conclusions Endoscopic resection of esthesioneuroblastoma has demonstrated similar oncologic control while reducing postoperative morbidity and mortality over transcranial approaches. This case reveals the potential to preserve olfaction while achieving en bloc endoscopic resection of early stage esthesioneuroblastoma

One-piece modified gasket seal technique

Objectives Review the effectiveness of a modified gasket seal technique utilizing a porous high-density polyethylene plate/rectus sheath fascia construct without fat grafting for primary closure of anterior defects following endoscopic skull base surgery. Design Retrospective review (2011-2012). Setting Single academic medical center. Methods A retrospective review of five patients who underwent expanded endoscopic endonasal surgery for various pathologies (two craniopharyngiomas, two tuberculum meningiomas, and one planum meningioma) was performed. Skull base closure was performed using a one-piece modified gasket seal technique. Primary outcome measures included postoperative cerebrospinal fluid (CSF) leaks and donor site morbidity. Results There were no postoperative CSF leaks. Two patients experienced aseptic meningitis treated with a 14-day course of steroids. Two patients experienced new postoperative chronic/recurrent sinusitis treated with oral antibiotics and topical nasal therapy. There was no donor site morbidity such as infection, hematoma, or hernias. Conclusions The one-piece modified gasket-seal closure is a safe and effective method for reconstruction of endonasal defects of the anterior skull base. Rectus sheath fascia is an appropriate dural substitute for free tissue grafting with low donor site morbidity. The construction of the one-piece graft significantly decreases operative time and lowers the learning curve for multilayered closure

Early-Stage Chronic Kidney Disease and Hip Fracture Mortality

Chronic kidney disease (CKD) is a documented risk factor for hip fracture mortality. CKD represents a spectrum of disease and there is no clear evidence differentiating the risk between patients with early versus end-stage CKD. The purpose of this study was to explore the relationship between the stages of CKD and mortality following operative treatment of hip fractures. Four hundred ninety-eight patients were analyzed; 81 were identified as having CKD. This study followed overall patient mortality at 90 days and at 1 year postoperatively. Patients with CKD had higher mortality at both 90 days and 1 year compared with those without CKD (hazard ratio 1.69 and 1.84, respectively). In a subgroup analysis to determine the effect of CKD stage, only stage 3 CKD was associated with increased mortality. The orthopaedic surgeon can play a key role in identifying at-risk patients and help to facilitate additional management. (Journal of Surgical Orthopaedic Advances 27(3):226-230, 2018)

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)

High-risk prescribing and monitoring in primary care:how common is it, and how can it be improved?

The safety of medication use in primary care is an area of increasing concern for health systems internationally. Systematic reviews estimate that 3–4% of all unplanned hospital admissions are due to preventable drug-related morbidity, the majority of which have been attributed to shortcomings in the prescribing and monitoring stages of the medication use process. We define high-risk prescribing as medication prescription by professionals, for which there is evidence of significant risk of harm to patients, and which should therefore either be avoided or (if avoidance is not possible) closely monitored and regularly reviewed for continued appropriateness. Although prevalence estimates vary depending on the instrument used, cross-sectional studies conducted in primary care equivocally show that it is common and there is evidence that it can be reduced. Quality improvement strategies, such as clinical decision support, performance feedback and pharmacist-led interventions have been shown to be effective in reducing prescribing outcomes but evidence of improved patient outcomes remains limited. The increasing implementation of electronic medical records in primary care offer new opportunities to combine different strategies to improve medication safety in primary care and to integrate services provided by different stakeholders. In this review article, we describe the spectrum of high-risk medication use in primary care, review approaches to its measurement and summarize research into its prevalence. Based on previously developed interventions to change professional practice, we propose a systematic approach to improve the safety of medication use in primary care and highlight areas for future research