Safety of high speed expressway signals: a comparison of classical and empirical Bayes methods

High speed expressways are becoming increasingly common as two-lane roads are improved to handle suburban traffic growth. Characterized by at-grade intersections and at least two lanes of traffic in each direction, these facilities are separated by a median and commonly have speed limits of 50 mph or greater. As traffic levels increase, stop controlled intersections are typically signalized to reduce delay or enhance safety. It is the safety performance of these signals that is the focus of this thesis. This thesis reports on a study investigating the safety benefit of signalizing intersections of high speed divided expressways. Cross classification, matched (yoked) pairs, before and after, and empirical Bayes (EB) analyses were conducted on 50&55-mph and 55-mph only intersections comparing unsignalized and signalized intersections. The results show that, generally, signalized intersections have a higher crash rate and lower costs per crash. However, in the before and after analysis (intersections that were signalized between 1994 and 2001), the after period experienced lower crash rates with higher costs per crash than before signalization. In the EB analysis, the crash rates changed from the before and after analysis (from 11.7% decrease to an 18.9% increase at the 50&55-mph intersections and from 31.4% decrease to a 6.8% decrease at the 55-mph only intersections)

The Impact of Dispersion on Amplitude and Frequency Noise in a Yb-fiber Laser Comb

We describe a Yb-fiber based laser comb, with a focus on the relationship between net-cavity dispersion and the frequency noise on the comb. While tuning the net cavity dispersion from anomalous to normal, we measure the amplitude noise (RIN), offset frequency (f_CEO) linewidth, and the resulting frequency noise spectrum on f_CEO. We find that the laser operating at zero net-cavity dispersion has many advantages, including an approximately 100x reduction in free-running f_CEO linewidth and frequency noise power spectral density between laser operation at normal and zero dispersion. In this latter regime, we demonstrate a phase-locked f_CEO beat with low residual noise

Power to the People: The Role of Humans in Interactive Machine Learning

Systems that can learn interactively from their end-users are quickly becoming widespread. Until recently, this progress has been fueled mostly by advances in machine learning; however, more and more researchers are realizing the importance of studying users of these systems. In this article we promote this approach and demonstrate how it can result in better user experiences and more effective learning systems. We present a number of case studies that demonstrate how interactivity results in a tight coupling between the system and the user, exemplify ways in which some existing systems fail to account for the user, and explore new ways for learning systems to interact with their users. After giving a glimpse of the progress that has been made thus far, we discuss some of the challenges we face in moving the field forward.This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by the American Association for Artificial Intelligence and can be found at: http://www.aaai.org/Magazine/magazine.php

Circulating 250HD, dietary vitamin D, PTH, and calcium associations with incident cardiovascular disease and mortality: The MIDSPAN Family Study

<p>Context: Observational studies relating circulating 25-hydroxyvitamin D (25OHD) and dietary vitamin D intake to cardiovascular disease (CVD) have reported conflicting results.</p> <p>Objective: Our objective was to investigate the association of 25OHD, dietary vitamin D, PTH, and adjusted calcium with CVD and mortality in a Scottish cohort.</p> <p>Design and Setting: TheMIDSPAN Family Study is a prospective study of 1040 men and 1298 women from the West of Scotland recruited in 1996 and followed up for a median 14.4 yr. Participants: Locally resident adult offspring of a general population cohort were recruited from 1972–1976.</p> <p>Main Outcome Measures: CVD events (n = 416) and all-cause mortality (n=100) were evaluated.</p> <p>Results: 25OHD was measured using liquid chromatography-tandem mass spectrometry in available plasma (n=2081). Median plasma 25OHD was 18.6 ng/ml, and median vitamin D intake was 3.2 µ g/d (128 IU/d). Vitamin D deficiency (25OHD<15 ng/ml) was present in 689 participants (33.1%). There was no evidence that dietary vitamin D intake, PTH, or adjusted calcium were associated with CVD events or with mortality. Vitamin D deficiency was not associated with CVD (fully adjusted hazard ratio=1.00; 95% confidence interval=0.77–1.31). Results were similar after excluding patients who reported an activity-limiting longstanding illness at baseline (18.8%) and those taking any vitamin supplements (21.7%). However, there was some evidence vitamin D deficiency was associated with all-cause mortality (fully adjusted hazard ratio=2.02; 95% confidence interval=1.17–3.51).</p> <p>Conclusion: Vitamin D deficiency was not associated with risk of CVD in this cohort with very low 25OHD. Future trials of vitamin D supplementation in middle-aged cohorts should be powered to detect differences inmortality outcomes as well as CVD.(J Clin EndocrinolMetab97: 0000 –0000, 2012)</p&gt

The distribution of estuarine fish larvae: nutritional condition and co-occurrence with predators and prey

Fish larvae were collected monthly between March and September 1997 in the Mira and Guadiana estuaries (southern Portugal). Hydrological parameters were registered and zooplankton samples were obtained simultaneously. Densities of fish larvae (ind.100 m(-3)) were calculated from 211 samples and larval nutritional condition measured as RNA/DNA ratios were obtained for 346 individuals, using a fluorimetric method for nucleic acid quantification. Correlating variables were further studied using multiple regression analysis in order to assess the relative importance of abiotic and biotic factors affecting within-year trends in abundance and nutritional condition of estuarine fish larvae. Results indicated that: 1) the abundance of fish larvae seems conditioned by temperature and predation; and 2) their nutritional condition is dependent on temperature and prey availability. Temperature is an important variable structuring estuaries and therefore conditions the behaviour and physiology of fish larvae. Furthermore, the co-occurrence of predators and larvae might be related to similar feeding patterns or comensalism. Whenever feeding conditions are suitable, they usually determine enhanced growth and nutritional condition. However, predation seems to control this latter relationship through its effect on larval mortality. (C) 2000 Editions scientifiques et Medicales Elsevier SAS.info:eu-repo/semantics/publishedVersio

Expert Consensus Guidelines for Stocking of Antidotes in Hospitals That Provide Emergency Care

We provide recommendations for stocking of antidotes used in emergency departments (EDs). An expert panel representing diverse perspectives (clinical pharmacology, medical toxicology, critical care medicine, hematology/oncology, hospital pharmacy, emergency medicine, emergency medical services, pediatric emergency medicine, pediatric critical care medicine, poison centers, hospital administration, and public health) was formed to create recommendations for antidote stocking. Using a standardized summary of the medical literature, the primary reviewer for each antidote proposed guidelines for antidote stocking to the full panel. The panel used a formal iterative process to reach their recommendation for both the quantity of antidote that should be stocked and the acceptable timeframe for its delivery. The panel recommended consideration of 45 antidotes; 44 were recommended for stocking, of which 23 should be immediately available. In most hospitals, this timeframe requires that the antidote be stocked in a location that allows immediate availability. Another 14 antidotes were recommended for availability within 1 hour of the decision to administer, allowing the antidote to be stocked in the hospital pharmacy if the hospital has a mechanism for prompt delivery of antidotes. The panel recommended that each hospital perform a formal antidote hazard vulnerability assessment to determine its specific need for antidote stocking. Antidote administration is an important part of emergency care. These expert recommendations provide a tool for hospitals that offer emergency care to provide appropriate care of poisoned patients

Social Class

Discussion of class structure in fifth-century Athens, historical constitution of theater audiences, and the changes in the comic representation of class antagonism from Aristophanes to Menander