Methodology for urban rail and construction technology research and development planning

A series of transit system visits, organized by the American Public Transit Association (APTA), was conducted in which the system operators identified the most pressing development needs. These varied by property and were reformulated into a series of potential projects. To assist in the evaluation, a data base useful for estimating the present capital and operating costs of various transit system elements was generated from published data. An evaluation model was developed which considered the rate of deployment of the research and development project, potential benefits, development time and cost. An outline of an evaluation methodology that considered benefits other than capital and operating cost savings was also presented. During the course of the study, five candidate projects were selected for detailed investigation; (1) air comfort systems; (2) solid state auxiliary power conditioners; (3) door systems; (4) escalators; and (5) fare collection systems. Application of the evaluation model to these five examples showed the usefulness of modeling deployment rates and indicated a need to increase the scope of the model to quantitatively consider reliability impacts

Systematic review with meta‐analysis: race‐specific effects of alcohol and tobacco on the risk of oesophageal squamous cell carcinoma

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/100284/1/apt12514.pd

Prevalence and risk factors for heterotopic gastric mucosa of the upper esophagus among men undergoing routine screening colonoscopy

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/112300/1/dote12221.pd

Bolus clearance in esophagogastric junction outflow obstruction is associated with strength of peristalsis

BackgroundA manometric diagnosis of esophagogastric junction outflow obstruction (EGJOO) without a mechanical cause creates a therapeutic conundrum. The aim of this study was to assess esophageal bolus clearance in EGJOO and assess manometric factors associated with clearance in EGJOO.MethodsBolus clearance was assessed using line‐tracing method and contour method to determine Complete Bolus Transit (CBT) and Functional Clearance (FC), respectively, on combined High‐Resolution Impedance Manometry (HRIM). HRIM studies of EGJOO patients, as well as a sample of achalasia types I‐III and asymptomatic controls, were retrospectively analyzed. In EGJOO, associations between Integrated Relaxation Pressure (IRP) or Distal Contractile Integral (DCI) and clearance were assessed using receiver‐operating‐characteristic (ROC) curves.Key ResultsSeventy‐five EGJOO, 28 achalasia, and 11 normal subjects were included. Agreement between CBT and FC was good (Kappa=0.75). CBT across swallows in each group was as follows: type I achalasia: 14%, type II achalasia: 8%, type III achalasia: 61%, EGJOO: 86%, and normal: 98% (p values .023, .006, and 610 mmHg‐s‐cm (accuracy 87.7%, P=.004). Complete Bolus Transit( CBT) across individual swallows was 97.8% when DCI>884 mmHg‐s‐cm (accuracy 81.9%, P900 mmHg‐s‐cm.Esophagogastric junction outflow obstruction (EGJOO) is a manometric diagnosis with unclear clinical significance. We studied bolus clearance in EGJOO, including in relationship to Distal Contractile Integral (DCI) and Integrated Relaxation Pressure (IRP). We found that intact peristalsis defined as a DCI of greater than 900 mmHg‐s‐cm is associated with complete bolus transit.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138211/1/nmo13093_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/138211/2/nmo13093.pd

The mechanical response of semiflexible networks to localized perturbations

Previous research on semiflexible polymers including cytoskeletal networks in cells has suggested the existence of distinct regimes of elastic response, in which the strain field is either uniform (affine) or non-uniform (non-affine) under external stress. Associated with these regimes, it has been further suggested that a new fundamental length scale emerges, which characterizes the scale for the crossover from non-affine to affine deformations. Here, we extend these studies by probing the response to localized forces and force dipoles. We show that the previously identified nonaffinity length [D.A. Head et al. PRE 68, 061907 (2003).] controls the mesoscopic response to point forces and the crossover to continuum elastic behavior at large distances.Comment: 16 pages, 18 figures; substantial changes to text and figures to clarify the crossover to continuum elasticity and the role of finite-size effect

Word Embeddings for Entity-annotated Texts

Learned vector representations of words are useful tools for many information retrieval and natural language processing tasks due to their ability to capture lexical semantics. However, while many such tasks involve or even rely on named entities as central components, popular word embedding models have so far failed to include entities as first-class citizens. While it seems intuitive that annotating named entities in the training corpus should result in more intelligent word features for downstream tasks, performance issues arise when popular embedding approaches are naively applied to entity annotated corpora. Not only are the resulting entity embeddings less useful than expected, but one also finds that the performance of the non-entity word embeddings degrades in comparison to those trained on the raw, unannotated corpus. In this paper, we investigate approaches to jointly train word and entity embeddings on a large corpus with automatically annotated and linked entities. We discuss two distinct approaches to the generation of such embeddings, namely the training of state-of-the-art embeddings on raw-text and annotated versions of the corpus, as well as node embeddings of a co-occurrence graph representation of the annotated corpus. We compare the performance of annotated embeddings and classical word embeddings on a variety of word similarity, analogy, and clustering evaluation tasks, and investigate their performance in entity-specific tasks. Our findings show that it takes more than training popular word embedding models on an annotated corpus to create entity embeddings with acceptable performance on common test cases. Based on these results, we discuss how and when node embeddings of the co-occurrence graph representation of the text can restore the performance.Comment: This paper is accepted in 41st European Conference on Information Retrieva

Indeterminacy of Spatiotemporal Cardiac Alternans

Cardiac alternans, a beat-to-beat alternation in action potential duration (at the cellular level) or in ECG morphology (at the whole heart level), is a marker of ventricular fibrillation, a fatal heart rhythm that kills hundreds of thousands of people in the US each year. Investigating cardiac alternans may lead to a better understanding of the mechanisms of cardiac arrhythmias and eventually better algorithms for the prediction and prevention of such dreadful diseases. In paced cardiac tissue, alternans develops under increasingly shorter pacing period. Existing experimental and theoretical studies adopt the assumption that alternans in homogeneous cardiac tissue is exclusively determined by the pacing period. In contrast, we find that, when calcium-driven alternans develops in cardiac fibers, it may take different spatiotemporal patterns depending on the pacing history. Because there coexist multiple alternans solutions for a given pacing period, the alternans pattern on a fiber becomes unpredictable. Using numerical simulation and theoretical analysis, we show that the coexistence of multiple alternans patterns is induced by the interaction between electrotonic coupling and an instability in calcium cycling.Comment: 20 pages, 10 figures, to be published in Phys. Rev.

Epidemiology, Diagnosis, and Management of Esophageal Adenocarcinoma

Esophageal adenocarcinoma (EAC) is rapidly increasing in incidence in Western cultures. Barrett’s esophagus (BE) is the presumed precursor lesion for this cancer. Several other risk factors for this cancer have been described, including chronic heartburn, tobacco use, Caucasian race, and obesity. Despite these known associations, most patients with EAC present with symptoms of dysphagia from late-stage tumors—only a small minority of patients are identified in screening and surveillance programs. Diagnostic analysis of EAC usually commences with upper endoscopy, followed by cross-sectional imaging. Endoscopic ultrasound is useful to assess local extent of disease as well as the involvement regional lymph nodes. T1a EAC may be treated endoscopically; some patients with T1b disease might also benefit from endoscopic therapy. Locally advanced disease is generally managed with esophagectomy, often accompanied by neoadjuvant chemoradiotherapy or chemotherapy. The prognosis is based on tumor stage: patients with T1a tumors have an excellent prognoses, whereas few patients with advanced disease have longterm survival

Cardiac Troponin Assessment Following Atrial Fibrillation Ablation: Implications for Chest Pain Evaluation

Background: The range of elevation of troponin I (tI) that is within expected limits from left atrial radiofrequency ablation for atrial fibrillation (AF) is not well described, though such information may be of clinical value. Objectives: Identify the expected range of tI values post-atrial fibrillation (AF) ablation. Methods: 31 patients undergoing AF ablation had a single tI level drawn the day following the procedure. Clinical variables were also collected, such as ablation type and radiofrequency (RF) time. Results: Paroxysmal AF was present in 23 patients, and 8 had chronic AF. The average RF time was 2627.8 ± 737.5 seconds. The mean RF power was 61.7 ± 4.3W (range 55-70W). The mean RF temperature limit was 53.6 ± 2.0°C (range 50-55°C). There was no clinical or electrocardiographic evidence of coronary ischemia in this population. The mean tI the following day was 3.21 ± 1.5 (range 1.48-8.41). There was no correlation between RF time, ablation type, ablation catheter size, and ablation temperature or ablation power and tI levels. Conclusions: Troponin I elevation post-ablation was ubiquitous. Knowledge of expected post-ablation tI levels may be helpful in the evaluation of post-procedure chest pain

Molecular weight effects on chain pull-out fracture of reinforced polymeric interfaces

Using Brownian dynamics, we simulate the fracture of polymer interfaces reinforced by diblock connector chains. We find that for short chains the interface fracture toughness depends linearly on the degree of polymerization $N$ of the connector chains, while for longer chains the dependence becomes $N^{3/2}$. Based on the geometry of initial chain configuration, we propose a scaling argument that accounts for both short and long chain limits and crossover between them.Comment: 5 pages, 3 figure