A planning model for intermodal auto-rail transportation assignment

This thesis presents a planning model for assigning trips in a corridor served by highways and commuter rail. The underlying assumption is that commuters will choose a mode (or a combination of modes) connecting the origin and destination in a way that will either minimize their individual travel times and costs (the user equilibrium principle) or minimize total system travel time and cost (system optimal principle). The model is structured as a mathematical program with a non-linear objective function and linear constraints. The model was applied to a case study of the Raritan Valley Corridor located in Northern New Jersey. The corridor primarily serves commuters from the western part of New Jersey who are destined to Newark. Potential benefits of introducing an Advanced Traveler Information Service (ATIS) for shifting commuters form auto to rail under various management strategies and levels of congestion are also discussed. The results showed that there was total system travel time savings when auto commuters were shifted to rail. In addition, it was found that as congestion increased the mode assignments made under different management strategies became more alike

Overheating and its effects on the toughness of astm a508 class ii forgings

The effect of overheating prior to forging of ASTM A508 Class 2 steel was the subject of this experimental investigation. The main areas of study were the influence of overheating followed forging and/or heat treatment on the impact fracture appearance and toughness of this grade

A Recursive Algorithm For Fractionally Differencing Long Data Series

We propose a recursive algorithm to fractionally difference time series data. The algorithm eliminates the need to evaluate the gamma function directly, and hence avoids the overflow problem that arises when fractionally differencing a long data series. The proposed algorithm can be implemented using any general matrix programming language. An implementation using SAS is presented. The algorithm and the code provide a practical approach to including fractional differencing as part of a time series data analysis

Endoscopic Papillary Balloon Dilation with Large Balloon after Limited Sphincterotomy for Retrieval of Choledocholithiasis

Endoscopic papillary balloon dilation (EBD) for choledocholithiasis is known to be comparable to endoscopic sphincterotomy (EST) especially in cases of small stones. With larger stones, EBD with conventional balloon, which have a diameter of 6-8 mm, was reported as less effective for extraction of stones. We evaluated the efficacy and complications of EBD with large balloons (10-15 mm) after limited EST for retrieval of choledocholithiasis. From February 2005, we have performed EBD with limited EST for retrieval of common bile duct (CBD) stones. The patients who admitted with hyperamylasemia and gallstone pancreatitis were excluded. In cases without CBD dilation, EPBD with 12 mm for 40 seconds was performed. And in cases with CBD dilation, we dilated the sphincters with 15 mm sized balloon for 40 seconds. Total 22 patients (11 of male) were performed EBD with limited EST for retrieval of CBD stones. The median diameter of the stones was 10 mm (5-25 mm). Ten cases had multiple stones and 6 cases periampullary diverticuli. Successful stone removal in the initial session of ERCP with EBD was accomplished in 16 patients (72.7%). And complete retrieval of bile duct stones was achieved in all patients with repeated ERCP. In the aspect of complications, any episodes of perforation, bleeding was not developed. Only one case of mild grade of post-procedural pancreatitis was noted. However, post-procedural hyperamylasemia was developed in 16 cases (68.2%). EBD with larger balloon seems to be a feasible and safe alternative technique for conventional EST in CBD stone extraction

Cost-effectiveness analysis of 3-D computerized tomography colonography versus optical colonoscopy for imaging symptomatic gastroenterology patients.

BACKGROUND: When symptomatic gastroenterology patients have an indication for colonic imaging, clinicians have a choice between optical colonoscopy (OC) and computerized tomography colonography with three-dimensional reconstruction (3-D CTC). 3-D CTC provides a minimally invasive and rapid evaluation of the entire colon, and it can be an efficient modality for diagnosing symptoms. It allows for a more targeted use of OC, which is associated with a higher risk of major adverse events and higher procedural costs. A case can be made for 3-D CTC as a primary test for colonic imaging followed if necessary by targeted therapeutic OC; however, the relative long-term costs and benefits of introducing 3-D CTC as a first-line investigation are unknown. AIM: The aim of this study was to assess the cost effectiveness of 3-D CTC versus OC for colonic imaging of symptomatic gastroenterology patients in the UK NHS. METHODS: We used a Markov model to follow a cohort of 100,000 symptomatic gastroenterology patients, aged 50 years or older, and estimate the expected lifetime outcomes, life years (LYs) and quality-adjusted life years (QALYs), and costs (£, 2010-2011) associated with 3-D CTC and OC. Sensitivity analyses were performed to assess the robustness of the base-case cost-effectiveness results to variation in input parameters and methodological assumptions. RESULTS: 3D-CTC provided a similar number of LYs (7.737 vs 7.739) and QALYs (7.013 vs 7.018) per individual compared with OC, and it was associated with substantially lower mean costs per patient (£467 vs £583), leading to a positive incremental net benefit. After accounting for the overall uncertainty, the probability of 3-D CTC being cost effective was around 60 %, at typical willingness-to-pay values of £20,000-£30,000 per QALY gained. CONCLUSION: 3-D CTC is a cost-saving and cost-effective option for colonic imaging of symptomatic gastroenterology patients compared with OC

Fiberoptic endoscopic evaluation of swallowing in intensive care unit patients

Aspiration in critically ill patients frequently causes severe co-morbidity. We evaluated a diagnostic protocol using routine FEES in critically ill patients at risk to develop aspiration following extubation. We instructed intensive care unit physicians on specific risk factors for and clinical signs of aspiration following extubation in critically ill patients and offered bedside FEES for such patients. Over a 45-month period, we were called to perform 913 endoscopic examinations in 553 patients. Silent aspiration or aspiration with acute symptoms (cough or gag reflex as the bolus passed into the trachea) was detected in 69.3% of all patients. Prolonged non-oral feeding via a naso-gastric tube was initiated in 49.7% of all patients. In 13.2% of patients, a percutaneous endoscopic gastrostomy was initiated as a result of FEES findings, and in 6.3% an additional tracheotomy to prevent aspiration had to be initiated. In 59 out of 258 patients (22.9%), tracheotomies were closed, and 30.7% of all 553 patients could be managed with the immediate onset of an oral diet and compensatory treatment procedures. Additional radiological examinations were not required. FEES in critically ill patients allows for a rapid evaluation of deglutition and for the immediate initiation of symptom-related rehabilitation or for an early resumption of oral feeding