Evaluation of Route Changes Utilizing High-Resolution GPS Bus Transit Data

Congestion and travel delay on urban roadways can influence operating costs and service attractiveness. This research uses high resolution bus data to examine sources of delay on urban arterials. A set of tools was created to help visualize trends in bus behavior and movement; this allowed larger traffic trends to be visualized along urban corridors and urban streets. By using buses as probes and examining aggregated bus behavior, contoured speed plots can be used to understand the behavior of roadways outside the zone of influence of bus stops. Speed plots can be utilized to discover trends and travel patterns with only a few days’ worth of data. Congestion and speed variation can be viewed by time of day and plots can help indicate delays caused by intersections, crosswalks, or bus stops. This type of information is important to transit authorities looking to improve bus running times and reliability. Congested areas can be detected and ranked. Speed plots can be utilized to reevaluate bus stop locations, e.g. near-side vs. far-side, and to identify locations where improvement are needed, e.g. queue jump lanes. Transportation agencies can also benefit from this type of information because arterial performance measures are difficult to estimate.https://pdxscholar.library.pdx.edu/trec_seminar/1139/thumbnail.jp

Gas Sorption and Luminescence Properties of a Terbium(III)-Phosphine Oxide Coordination Material with Two-Dimensional Pore Topology

The structure, stability, gas sorption properties and luminescence behaviour of a new lanthanide-phosphine oxide coordination material are reported. The polymer PCM-15 is based on Tb(III) and tris(p-carboxylated) triphenylphosphine oxide and has a 5,5-connected net topology. It exhibits an infinite three-dimensional structure that incorporates an open, two-dimensional pore structure. The material is thermally robust and remains crystalline under high vacuum at 150 degrees C. When desolvated, the solid has a CO2 BET surface area of 1187 m(2) g(-1) and shows the highest reported uptake of both O-2 and H-2 at 77 K and 1 bar for a lanthanide-based coordination polymer. Isolated Tb(III) centres in the as-synthesized polymer exhibit moderate photoluminescence. However, upon removal of coordinated OH2 ligands, the luminescence intensity was found to approximately double; this process was reversible. Thus, the Tb(III) centre was used as a probe to detect directly the desolvation and resolvation of the polymer.Welch Foundation F-1738, F-1631National Science Foundation 0741973, CHE-0847763Chemistr

Resilabificación incompleta y acoplamiento gestual ambisilábico en español

In the generative literature, the pattern of coronal fricative lenition found in the traditional Chinato Spanish dialect is commonly cited as a phonological argument that the resyllabification of word-final prevocalic consonants is complete, in the sense that onsets derived by resyllabification are structurally identical to canonical (word-level) onsets. However, recent acoustic studies of Northern-Central Peninsular Spanish have problematized the completeness of resyllabification with experimental evidence that /s̺/ is shorter and more voiced as a derived onset than as a canonical onset. Using a split-gesture, competitive, coupled oscillator model of the syllable in Articulatory Phonology, which divides consonants into a separate constriction and release gesture, we propose a novel representation of ambisyllabicity that predicts the phonetic behavior of derived onset /s̺/ in Northern-Central Peninsular Spanish. We then show that ambisyllabic coupling permits a simpler phonological analysis of coronal fricative lenition in Chinato Spanish as compared to alternative accounts. Our analysis makes typological predictions that are confirmed by patterns from other contemporary Spanish varieties. Lastly, we examine the consequences of ambisyllabicity for the analysis of Spanish rhotic consonants, which have also been argued to support complete resyllabification. We offer an analysis of rhotics that is entirely compatible with an ambisyllabic representation of incomplete resyllabification.En la literatura generativa, el debilitamiento de fricativas coronales en el dialecto chinato del español peninsular se cita comúnmente como un argumento fonológico a favor de la resilabificación completa de consonantes prevocálicas finales de palabra, o sea que los arranques derivados por resilabificación son idénticos estructuralmente a los arranques canónicos a nivel de palabra. Sin embargo, algunos estudios acústicos recientes han problematizado la resilabificación completa en el español peninsular centro-norteño al presentar evidencia experimental de que la /s̺/ es más corta y sonorizada como arranque derivado que como arranque canónico. Utilizamos un modelo de acoplamiento competitivo desde la Fonología Articulatoria, el cual divide a las consonantes en un gesto de constricción y de soltura, para proponer una nueva representación de la ambisilabicidad que predice el comportamiento fonético de la /s̺/ como arranque derivado en el español peninsular centro-norteño. Luego, demostramos que el acoplamiento ambisilábico permite analizar mejor el debilitamiento de fricativas coronales en el español chinato, en comparación con otras explicaciones alternativas. Confirmamos las predicciones tipológicas de nuestro análisis para otras variedades contemporáneas del español. Por último, examinamos las consecuencias de la ambisilabicidad para el análisis de las consonantes róticas del español, también citadas como otro argumento a favor de la resilabificación completa. Ofrecemos un análisis de las róticas que es totalmente compatible con una representación ambisilábica de la resilabificación incompleta

Quantification of avian hazards to military aircraft and implications for wildlife management

Collisions between birds and military aircraft are common and can have catastrophic effects. Knowledge of relative wildlife hazards to aircraft (the likelihood of aircraft damage when a species is struck) is needed before estimating wildlife strike risk (combined frequency and severity component) at military airfields. Despite annual reviews of wildlife strike trends with civil aviation since the 1990s, little is known about wildlife strike trends for military aircraft. We hypothesized that species relative hazard scores would correlate positively with aircraft type and avian body mass. Only strike records identified to species that occurred within the U.S. (n = 36,979) and involved United States Navy or United States Air Force aircraft were used to calculate relative hazard scores. The most hazardous species to military aircraft was the snow goose (Anser caerulescens), followed by the common loon (Gavia immer), and a tie between Canada goose (Branta canadensis) and black vulture (Coragyps atratus). We found an association between avian body mass and relative hazard score (r2 = 0.76) for all military airframes. In general, relative hazard scores per species were higher for military than civil airframes. An important consideration is that hazard scores can vary depending on aircraft type. We found that avian body mass affected the probability of damage differentially per airframe. In the development of an airfield wildlife management plan, and absent estimates of species strike risk, airport wildlife biologists should prioritize management of species with high relative hazard scores

Frontal vehicle illumination via rear-facing lighting reduces potential for collisions with white-tailed deer

nimal–vehicle collisions cause many millions of animal deaths each year worldwide and present a substantial safety risk to people. In the United States and Canada, deer (Odocoileus spp.) are involved in most animal–vehicle collisions associated with human injuries. We evaluated a vehicle-based collision mitigation method designed to decrease the likelihood of deer–vehicle collisions during low-light conditions, when most collisions occur. Specifically, we investigated whether the use of a rear-facing light, providing more complete frontal vehicle illumination than standard headlights alone, enhanced vehicle avoidance behaviors of white-tailed deer (O. virginianus). We quantified flight initiation distance (FID), the likelihood of a dangerous deer–vehicle interaction (FID ≤ 50 m), and road-crossing behavior of deer in response to an oncoming vehicle using only standard high-beam headlights and the same vehicle using headlights plus an LED light bar illuminating the frontal surface of the vehicle. We predicted that frontal vehicle illumination would enhance perceived risk of deer approached by the vehicle and lead to more effective avoidance responses. We conducted 62 vehicle approaches (31 per lighting treatment) toward free-ranging deer over ~14 months. Although FID did not differ across treatments, the likelihood of a dangerous deer–vehicle interaction decreased from 35% of vehicle approaches using only headlights to 10% of vehicle approaches using the light bar. The reduction in dangerous interactions appeared to be driven by fewer instances of immobility (freezing) behavior by deer in response to the illuminated vehicle (n = 1) compared with approaches using only headlights (n = 10). Because more deer moved in response to the illuminated vehicle, road-crossing behavior likewise increased when the light bar was on, although these road crossings primarily occurred at FIDs \u3e 50 m and thus did not increase collision risk. Road-crossing behavior was influenced heavily by proximity to concealing cover; deer only crossed when the nearest cover was located on the opposite side of the road. We contend that frontal vehicle illumination via rearfacing lighting has potential to greatly reduce vehicle collisions with deer and other species. Future work should explore fine-tuning the method with regard to the visual capabilities of target species

Quantification of avian hazards to military aircraft and implications for wildlife management

Collisions between birds and military aircraft are common and can have catastrophic effects. Knowledge of relative wildlife hazards to aircraft (the likelihood of aircraft damage when a species is struck) is needed before estimating wildlife strike risk (combined frequency and severity component) at military airfields. Despite annual reviews of wildlife strike trends with civil aviation since the 1990s, little is known about wildlife strike trends for military aircraft. We hypothesized that species relative hazard scores would correlate positively with aircraft type and avian body mass. Only strike records identified to species that occurred within the U.S. (n = 36,979) and involved United States Navy or United States Air Force aircraft were used to calculate relative hazard scores. The most hazardous species to military aircraft was the snow goose (Anser caerulescens), followed by the common loon (Gavia immer), and a tie between Canada goose (Branta canadensis) and black vulture (Coragyps atratus). We found an association between avian body mass and relative hazard score (r2 = 0.76) for all military airframes. In general, relative hazard scores per species were higher for military than civil airframes. An important consideration is that hazard scores can vary depending on aircraft type. We found that avian body mass affected the probability of damage differentially per airframe. In the development of an airfield wildlife management plan, and absent estimates of species strike risk, airport wildlife biologists should prioritize management of species with high relative hazard scores

Collective Effect of Landfills and Landscape Composition on Bird–Aircraft Collisions

Ninety-three percent of all reported bird strikes occur below 1,067 m, which based on the typical approach and departure angles of aircraft is within 8–13 km of an airport. Concomitantly, the Federal Aviation Administration and the International Civil Aviation Organization recommend that any feature that would attract hazardous wildlife to the approach and departure airspace be restricted. Thus, preventing the establishment of wildlife attractants, such as municipal solid waste landfills (MSWLFs) within 8 km or 13 km extents (U.S. and international recommendations, respectively) of airports, has been recommended to mitigate the risk of bird–aircraft collisions (strikes). However, robust evidence linking wildlife attractants at these spatial scales to an increase in strikes is lacking. We investigated the effect of densities of MSWLFs and construction and demolition (C&D) landfills, landscape diversity, and human population density on the adverse effect (AE; strikes that caused damage or had a negative effect on flight) bird strike rate involving species broadly associated with MSWLFs. We predicted that airports surrounded by a high density of MSWLFs, high human population densities, and high landscape diversity would increase the AE strike rate. We evaluated our predictions via generalized linear mixed models with bird strike data from 2009 through 2017 at 111 Part 139 airports. Only U.S. airports were used because of high wildlife strike reporting rates. Part 139 certificated airports are those that facilitate air carriers with \u3e30 seats for passengers and crew. Our average model included density of MSWLFs and C&D landfills for both the 8- and 13-km extent from the airports. We found no significant contribution by any variable to the AE strike rate variance. Our results indicated that the effects of landfills on AE strike rates are inconclusive. Possible explanations for our findings include the influence of unmeasured landscape features and lack of fine-scale data on bird habitat use at landfill facilities. Future research should investigate bird 3-dimensional space use in addition to bird and habitat survey techniques