Time-dependent stochastic shortest path(s) algorithms for a scheduled transportation network

Following on from our work concerning travellers’ preferences in public transportation networks (Wu and Hartley, 2004), we introduce the concept of stochasticity to our algorithms. Stochasticity greatly increases the complexity of the route finding problem, so greater algorithmic efficiency becomes imperative. Public transportation networks (buses, trains) have two important features: edges can only be traversed at certain points in time and the weights of these edges change in a day and have an uncertainty associated with them. These features determine that a public transportation network is a stochastic and time-dependent network. Finding multiple shortest paths in a both stochastic and time-dependent network is currently regarded as the most difficult task in the route finding problems (Loui, 1983). This paper discusses the use of k-shortest-paths (KSP) algorithms to find optimal route(s) through a network in which the edge weights are defined by probability distributions. A comprehensive review of shortest path(s) algorithms with probabilistic graphs was conducted

Confidence regions for variance ratios in variance components models

Statistical mechanics for constructing confidence intervals for variance ratios in balanced and unbalanced experimental design

Development of innovative cross-disciplinary engineering showcase

The development of engineering education relies substantially on interactive showcases and practical knowledge. The cross-disciplinary engineering showcase is designed to be fully interactive by having user input, producing a tangible output, and to understand distinct elements from each of the engineering disciplines such as, civil, mechanical and electrical (CME). The showcase operates from the input of mechanical rotational energy by the user pedalling the exercycle. Mechanical energy is then transferred to the pump via a gear train, which converts the user input of 30 rpm to the optimal pump operating speed of 2900 rpm. Further, it is used to pump water from the lower eservoir to the upper reservoir via one of the three flow paths, which the user can select by opening or closing flow valves. Once the water reaches a given height, it then flows back to the lower reservoir via a micro-hydro generator. As a result, it generates electrical energy stored in a power bank that can be used by the user to charge a digital device. Also, the showcase has a QR code to digital media, which will provide an additional explanation/exposition of the presented engineering principles to the user/students. The aim of this project is to develop a cross- disciplinary engineering showcase to enhance student learnings by interpreting the CME engineering principles in schools, institutes, and universities

Development of innovative cross-disciplinary engineering showcase

The development of engineering education relies substantially on interactive showcases and practical knowledge. The cross-disciplinary engineering showcase is designed to be fully interactive by having user input, producing a tangible output, and to understand distinct elements from each of the engineering disciplines such as, civil, mechanical and electrical (CME). The showcase operates from the input of mechanical rotational energy by the user pedalling the exercycle. Mechanical energy is then transferred to the pump via a gear train, which converts the user input of 30 rpm to the optimal pump operating speed of 2900 rpm. Further, it is used to pump water from the lower eservoir to the upper reservoir via one of the three flow paths, which the user can select by opening or closing flow valves. Once the water reaches a given height, it then flows back to the lower reservoir via a micro-hydro generator. As a result, it generates electrical energy stored in a power bank that can be used by the user to charge a digital device. Also, the showcase has a QR code to digital media, which will provide an additional explanation/exposition of the presented engineering principles to the user/students. The aim of this project is to develop a cross- disciplinary engineering showcase to enhance student learnings by interpreting the CME engineering principles in schools, institutes, and universities

Impact of the COVID-19 pandemic on daily life, mood, and behavior of adults with Down syndrome

BACKGROUND: The Down syndrome population has been disproportionately affected by Coronavirus 2019 (COVID-19) in terms of experiencing severe illness and death. Societal efforts to curb the spread of COVID-19 may also have taken a heavy toll on the daily lives of individuals with Down syndrome. OBJECTIVE/HYPOTHESIS: The goal of the study was to understand how the COVID-19 pandemic has altered daily life (including residence, employment, and participation in adult disability day programs) and influenced the mood and behavior of adults with Down syndrome. METHODS: Between September 2020 and February 2021, caregivers of 171 adults with Down syndrome (aged 22-66 years) located across the United States and in the United Kingdom enrolled in the Alzheimer\u27s Biomarker Research Consortium on Down Syndrome (ABC-DS) completed a survey. RESULTS: The residence of 17% of individuals was altered, and 89% of those who had been employed stopped working during the pandemic. One-third (33%) of individuals were reported to be more irritable or easily angered, 52% were reported to be more anxious, and 41% were reported to be more sad/depressed/unhappy relative to prepandemic. The majority of changes in mood and behavior were of modest severity. CONCLUSIONS: The COVID-19 pandemic has had widespread effects on the daily life and mood and behavior of adults with Down syndrome. In the short term, caregivers and providers should be prepared to help adults with Down syndrome with changes in daily routines, residence, employment, or adult disability day programs as society shifts away from COVID-19 safety protocols

Are Rural Health Clinics Part of the Rural Safety Net?

Key Findings: 86% of independent RHCs offer free care, sliding fee scales, or both; 97% were currently accepting new Medicaid/SCHIP patients; RHCs\u27 patient mix has a higher proportion of Medicaid/SCHIP patients in counties not served by a federally funded Community Health Center (CHC). Lacking the grant funds and federal technical assistance provided to CHCs to build service capacity, few RHCs have had the resources to expand their scope of services. The Affordable Care Act has made it clear that partnering with CHCs is an option for RHCs that find themselves serving safety net populations. More study is needed laying out the details of such arrangements, the reimbursement and governance implications, and the relative advantages and disadvantages from the perspectives of the CHC, the RHC, the physician, and especially, the patient

Safety Net Activities of Independent Rural Health Clinics

Rural Health Clinics (RHCs) are an important part of the rural health care infrastructure as they provide a wide range of primary care services to the rural residents of 45 states. Since RHCs are located in underserved rural areas and serve vulnerable populations, many consider them safety net providers. In this paper we explore whether and to what extent independent RHCs are serving a safety net role, or have the capacity to serve that role. We address this question through a telephone survey of 392 randomly selected independent RHCs. Response rate for the survey was 93%. We investigated whether and to what extent RHCs offer free or discounted care and serve Medicaid populations. We also sought to determine if the proximity of a federally funded Community Health Center might have an effect on the extent to which an RHC serves the safety net role. Key Findings: 86% of the RHCs surveyed provide free or discounted care, and an estimated 27% of their visits are from Medicaid patients, although only 47% reported that they help their patients enroll in Medicaid; proximity of a Community Health Center, either in the same county or in the same zip code, was not associated with offering free or discounted care, but was associated with the percentage of total patient visits attributable to Medicaid patients; using 30% or more of patients on Medicaid as a threshold, we found that RHCs with a CHC in the same county were significantly less likely to meet this threshold (38%) as compared with RHCs without a CHC in their county (65%)

Safety Net Activities of Independent Rural Health Clinics

Rural Health Clinics (RHCs) are an important part of the rural health care infrastructure as they provide a wide range of primary care services to the rural residents of 45 states. Since RHCs are located in underserved rural areas and serve vulnerable populations, many consider them safety net providers. In this paper we explore whether and to what extent independent RHCs are serving a safety net role, or have the capacity to serve that role. We address this question through a telephone survey of 392 randomly selected independent RHCs. Response rate for the survey was 93%. We investigated whether and to what extent RHCs offer free or discounted care and serve Medicaid populations. We also sought to determine if the proximity of a federally funded Community Health Center might have an effect on the extent to which an RHC serves the safety net role. Key Findings: 86% of the RHCs surveyed provide free or discounted care, and an estimated 27% of their visits are from Medicaid patients, although only 47% reported that they help their patients enroll in Medicaid; proximity of a Community Health Center, either in the same county or in the same zip code, was not associated with offering free or discounted care, but was associated with the percentage of total patient visits attributable to Medicaid patients; using 30% or more of patients on Medicaid as a threshold, we found that RHCs with a CHC in the same county were significantly less likely to meet this threshold (38%) as compared with RHCs without a CHC in their county (65%)

Logarithmic rate dependence in deforming granular materials

Rate-independence for stresses within a granular material is a basic tenet of many models for slow dense granular flows. By contrast, logarithmic rate dependence of stresses is found in solid-on-solid friction, in geological settings, and elsewhere. In this work, we show that logarithmic rate-dependence occurs in granular materials for plastic (irreversible) deformations that occur during shearing but not for elastic (reversible) deformations, such as those that occur under moderate repetitive compression. Increasing the shearing rate, \Omega, leads to an increase in the stress and the stress fluctuations that at least qualitatively resemble what occurs due to an increase in the density. Increases in \Omega also lead to qualitative changes in the distributions of stress build-up and relaxation events. If shearing is stopped at t=0, stress relaxations occur with \sigma(t)/ \sigma(t=0) \simeq A \log(t/t_0). This collective relaxation of the stress network over logarithmically long times provides a mechanism for rate-dependent strengthening.Comment: 4 pages, 5 figures. RevTeX

Predicting Ebola infection: A malaria-sensitive triage score for Ebola virus disease.

The non-specific symptoms of Ebola Virus Disease (EVD) pose a major problem to triage and isolation efforts at Ebola Treatment Centres (ETCs). Under the current triage protocol, half the patients allocated to high-risk "probable" wards were EVD(-): a misclassification speculated to predispose nosocomial EVD infection. A better understanding of the statistical relevance of individual triage symptoms is essential in resource-poor settings where rapid, laboratory-confirmed diagnostics are often unavailable. This retrospective cohort study analyses the clinical characteristics of 566 patients admitted to the GOAL-Mathaska ETC in Sierra Leone. The diagnostic potential of each characteristic was assessed by multivariate analysis and incorporated into a statistically weighted predictive score, designed to detect EVD as well as discriminate malaria. Of the 566 patients, 28% were EVD(+) and 35% were malaria(+). Malaria was 2-fold more common in EVD(-) patients (p<0.05), and thus an important differential diagnosis. Univariate analyses comparing EVD(+) vs. EVD(-) and EVD(+)/malaria(-) vs. EVD(-)/malaria(+) cohorts revealed 7 characteristics with the highest odds for EVD infection, namely: reported sick-contact, conjunctivitis, diarrhoea, referral-time of 4-9 days, pyrexia, dysphagia and haemorrhage. Oppositely, myalgia was more predictive of EVD(-) or EVD(-)/malaria(+). Including these 8 characteristics in a triage score, we obtained an 89% ability to discriminate EVD(+) from either EVD(-) or EVD(-)/malaria(+). This study proposes a highly predictive and easy-to-use triage tool, which stratifies the risk of EVD infection with 89% discriminative power for both EVD(-) and EVD(-)/malaria(+) differential diagnoses. Improved triage could preserve resources by identifying those in need of more specific differential diagnostics as well as bolster infection prevention/control measures by better compartmentalizing the risk of nosocomial infection