bluuebunny/crossref_metadata_2025 huggingface dataset:
Blood Pressure-Attained Analysis of ATACH 2 Trial
Authors: Qureshi Adnan I. , Palesch Yuko Y. , Foster Lydia D. , Barsan William G. , Goldstein Joshua N. , Hanley Daniel F. , Hsu Chung Y. , Moy Claudia S. , Qureshi Mushtaq H. , Silbergleit Robert , Suarez Jose I. , Toyoda Kazunori , Yamamoto Haruko ,   on behalf of ATACH 2 Trial Investigators*
Published: May 2018

Background and Purpose—

We compared the rates of death or disability, defined by modified Rankin Scale score of 4 to 6, at 3 months in patients with intracerebral hemorrhage according to post-treatment systolic blood pressure (SBP)–attained status.

Methods—

We divided 1000 subjects with SBP ≥180 mm Hg who were randomized within 4.5 hours of symptom onset as follows: SBP <140 mm Hg achieved or not achieved within 2 hours; subjects in whom SBP <140 mm Hg was achieved within 2 hours were further divided: SBP <140 mm Hg for 21 to 22 hours (reduced and maintained) or SBP was ≥140 mm Hg for at least 2 hours during the period between 2 and 24 hours (reduced but not maintained).

Results—

Compared with subjects without reduction of SBP <140 mm Hg within 2 hours, subjects with reduction and maintenance of SBP <140 mm Hg within 2 hours had a similar rate of death or disability (relative risk of 0.98; 95% confidence interval, 0.74–1.29). The rates of neurological deterioration within 24 hours were significantly higher in reduced and maintained group (10.4%; relative risk, 1.98; 95% confidence interval, 1.08–3.62) and in reduced but not maintained group (11.5%; relative risk, 2.08; 95% confidence interval, 1.15–3.75) compared with reference group. The rates of cardiac-related adverse events within 7 days were higher among subjects with reduction and maintenance of SBP <140 mmHg compared to subjects without reduction (11.2% versus 6.4%).

Conclusions—

No decline in death or disability but higher rates of neurological deterioration and cardiac-related adverse events were observed among intracerebral hemorrhage subjects with reduction with and without maintenance of intensive SBP goals.

Clinical Trial Registration—

URL:
https://www.clinicaltrials.gov
. Unique identifier: NCT01176565.
Investigating Head Movements Induced by ‘Riloid’ Patterns in Migraine and Control Groups Using a Virtual Reality Display
Authors: O’Hare Louise , Sharp Alex , Dickinson Patrick , Richardson Graham , Shearer John
Published: May 2018

Certain striped patterns can induce illusory motion, such as those used in op-art. The visual system and the vestibular system work together closely, and so it is possible that illusory motion from a visual stimulus can result in uncertainty in the vestibular system. This increased uncertainty may be measureable in terms of the magnitude of head movements. Head movements were measured using a head-mounted visual display. Results showed that stimuli associated with illusory motion also seem to induce greater head movements when compared to similar stimuli. Individuals with migraine are more susceptible to visual discomfort, and this includes illusory motion from striped stimuli. However, there was no evidence of increased effect of illusory motion on those with migraine compared to those without, suggesting that while motion illusions may affect discomfort judgements, this is not limited to only those with migraine.
The Thrive Mosaic Developmental Framework: A Systems Activist Approach to Marginalized STEM Scholar Success
Authors: Chapman Robbin N.
Published: May 2018

The science of broadening participation explains how science thrives with appropriate frameworks for addressing complex issues. This article presents a developmental framework for equitable STEM scholar development, access, and opportunity. Few issues in academia are more complex than ensuring all scholars can thrive without unwarranted obstacles of intentional disruption or benign indifference. The Thrive Mosaic developmental framework coalesces the best elements of a scholar’s networks to support scholar development, advocacy, and self-care, while also working to forestall systemic marginalization and obstructionist practices. The framework uses a systems thinking approach where aspects of the “ecology of academia” important to scholar success are conceptualized as systems that can be adapted to benefit the scholar and support scholar activism. The goal is to mitigate environmental internal and external factors that impede scholar success. Thrive Mosaic is both a resource and a tool for realizing scholar thriving, particularly within privileged and noncollegial environments.
Interlocking Inequalities: Digital Stratification Meets Academic Stratification
Authors: Robinson Laura , Wiborg Øyvind , Schulz Jeremy
Published: May 2018

This article examines the effects of digital inequality in conjunction with curricular tracking on academic achievement. Capitalizing on an original survey administered to seniors (fourth-year secondary school students), our survey data ( N = 972) come from a large American public high school with a predominantly disadvantaged student body. The school’s elective tracking system and inadequate digital resources make for an excellent case study of the effects of a differentiated curriculum and digital inequalities on academic achievement. Multilevel random-effects and fixed-effects regression models applied to the survey data reveal the important role played by digital inequalities in shaping academic achievement as measured by GPA. As the models establish, academic achievement is positively correlated with both duration of digital experience and usage intensity regarding academically useful computing activities, even when students’ curricular and class placement are taken into account. In contrast, both leisure computing and smartphone usage are negatively correlated with academic achievement as measured by GPA. Also with regard to GPA, findings show that students in the higher curricular tracks benefit more from longer durations of digital experience than do students in lower curricular tracks. These results underscore the importance of focusing attention on the ways in which digital inequalities combine with curricular tracking in shaping academic achievement.
A Method for Examining the Equating of Psychometric Scales and Tests: An Application Using Dementia Screening Test Batteries
Authors: Dowling N. Maritza , Raykov Tenko , Marcoulides George A.
Published: May 2018

Equating of psychometric scales and tests is frequently required and conducted in educational, behavioral, and clinical research. Construct comparability or equivalence between measuring instruments is a necessary condition for making decisions about linking and equating resulting scores. This article is concerned with a widely applicable method for examining if two scales or tests cannot be equated. A latent variable modeling method is discussed that can be used to evaluate whether the tests or parts thereof measure latent constructs that are distinct from each other. The approach can be routinely used before an equating procedure is undertaken, in order to assess whether equating could be meaningfully carried out to begin with. The procedure is readily applicable in empirical research using popular software. The method is illustrated with data from dementia screening test batteries administered as part of two studies designed to evaluate a wide range of biomarkers throughout the process of normal aging to dementia or Alzheimer’s disease.
Is Hinduism ambivalent about suicide?
Authors: Vijayakumar Lakshmi , John Sujit
Published: May 2018

Background:

Hinduism is one of the oldest religions in the world and has over 1.1 billion adherents comprising about 16% of the global population living mainly in India and Nepal. The stand of Hinduism on suicide has been ambiguous through the ages, on one hand, condemning general suicides, while condoning religious suicides on the other. This ambiguity is reflected in contemporary India and among the Indian diaspora.

Aims:

To examine the stand of Hinduism as a religion in the context of suicide.

Method:

A selected review of literature covering the major Hindu religious texts, cultural practices and suicide.

Results:

People who follow Hinduism have a suicide rate of about 21 per 100,000 population compared to the global average of 11.4. Hindu countries have higher rates of suicide compared to Islamic and Christian countries, but these rates are lower when compared to Atheist and Buddhist countries. This is reflected in the Indian diaspora as well with reports from Fiji, the Caribbean, Malaysia and the United Kingdom, indicating that suicide was disproportionately high among those of Indian origin. However, a strong faith in Hinduism acts as protective factor. The Hindu belief in karma fosters a sense of acceptance of the vicissitudes of life with equanimity, and the belief in the cycle of births and deaths renders suicide meaningless, as one’s soul continues after death. Their religious beliefs makes the Hindus tolerate and accept hardships and calamities stoically.

Conclusion:

In certain situations, the Hindu religion acts as a protective factor, whereas at other times, it may increase the risk of suicide. It is important to understand these different nuances in the Hindu religion in formulating a culturally appropriate suicide prevention strategy.
Effects of sodium citrate, citric acid and lactic acid on human blood coagulation
Authors: Scaravilli Vittorio , Di Girolamo Luca , Scotti Eleonora , Busana Mattia , Biancolilli Osvaldo , Leonardi Patrizia , Carlin Andrea , Lonati Caterina , Panigada Mauro , Pesenti Antonio , Zanella Alberto
Published: May 2018

Introduction:

Citric acid infusion in extracorporeal blood may allow concurrent regional anticoagulation and enhancement of extracorporeal CO2 removal. Effects of citric acid on human blood thromboelastography and aggregometry have never been tested before.

Methods:

In this in vitro study, citric acid, sodium citrate and lactic acid were added to venous blood from seven healthy donors, obtaining concentrations of 9 mEq/L, 12 mEq/L and 15 mEq/L. We measured gas analyses, ionized calcium (iCa++) concentration, activated clotting time (ACT), thromboelastography and multiplate aggregometry. Repeated measure analysis of variance was used to compare the acidifying and anticoagulant properties of the three compounds.

Results:

Sodium citrate did not affect the blood gas analysis. Increasing doses of citric and lactic acid progressively reduced pH and HCO3− and increased pCO2 (p<0.001). Sodium citrate and citric acid similarly reduced iCa++, from 0.39 (0.36-0.39) and 0.35 (0.33-0.36) mmol/L, respectively, at 9 mEq/L to 0.20 (0.20-0.21) and 0.21 (0.20-0.23) mmol/L at 15 mEq/L (p<0.001). Lactic acid did not affect iCa++ (p=0.07). Sodium citrate and citric acid similarly incremented the ACT, from 234 (208-296) and 202 (178-238) sec, respectively, at 9 mEq/L, to >600 sec at 15 mEq/L (p<0.001). Lactic acid did not affect the ACT values (p=0.486). Sodium citrate and citric acid similarly incremented R-time and reduced α-angle and maximum amplitude (MA) (p<0.001), leading to flat-line thromboelastograms at 15 mEq/L. Platelet aggregometry was not altered by any of the three compounds.

Conclusions:

Citric acid infusions determine acidification and anticoagulation of blood similar to lactic acid and sodium citrate, respectively.
A new method for visualizing pulmonary artery microvasculature using synchrotron radiation pulmonary microangiography: the measurement of pulmonary arterial blood flow velocity in the high pulmonary blood flow rat model
Authors: Tokunaga Chiho , Matsushita Shonosuke , Sakamoto Hiroaki , Hyodo Kazuyuki , Kubota Misao , Tanioka Kenkichi , Hiramatsu Yuji
Published: May 2018

Background

Increased pulmonary blood flow (PBF) and shear stress may provoke irreversible vascular remodeling, yet invasive visualization of the microvasculature complicates monitoring. A non-invasive imaging methodology would therefore safely provide mechanistic insights into the progression of high PBF-induced vascular remodeling.

Purpose

To establish a novel microvasculature visualization method using synchrotron radiation pulmonary microangiography (SRPA) that can also calculate PBF velocity in vivo.

Material and Methods

A high PBF rat model was established by making a fistula between the abdominal aorta and inferior vena cava. After eight weeks, SRPA was performed and the dynamic density changes in the right lower pulmonary artery (PA) were calculated by software. SRPA was performed with a HARP (High-Gain Avalanche Rushing amorphous Photoconductor) receiver. PBF velocity was calculated by contrast medium transit time within the PA. All data were presented as mean ± standard error (SE). Student's t-test was used for comparison between the two groups.

Results

High dynamic spatial and contrast resolution from SRPA in the PA allowed for clear pulmonary microangiography and accurate detection of higher PBF in the rat model (82.3 ± 8.5 mm/s high-PBF group vs. 46.1 ± 4.3 mm/s control group, P < 0.01).

Conclusions

These novel results demonstrate that SRPA was useful in both visualizing the dynamic flow distribution within the microvasculature and calculating PBF velocity. This newly developed, non-invasive technology may become a powerful tool in clarifying the mechanism of vascular remodeling associated with high PBF-induced shear stress.
Hyperbaric oxygen inhibits production of CD3+ T cells in the thymus and facilitates malignant glioma cell growth
Authors: Wang Yong-Gang , Long Jiang , Shao Dong-Chuan , Song Hai
Published: May 2018

Objective

Hyperbaric oxygen (HBO) is an emerging complementary alternative medical approach in glioma treatment. However, its mode of action is unknown, so this was investigated in the present study.

Methods

We constructed an intracranial glioma model of congenic C57BL/6J mice. Glioma growth under HBO stimulation was assessed by bioluminescent imaging and magnetic resonance imaging. Flow cytometry assessed direct effects of HBO on reactive oxygen species (ROS) signaling of transplanted glioma cells and organs, and quantified mature T cells and subgroups in tumors, the brain, and blood.

Results

HBO promoted the growth of transplanted GL261-Luc glioma in the intracranial glioma mouse model. ROS signaling of glioma cells and brain cells was significantly downregulated under HBO stimulation, but thymus ROS levels were significantly upregulated. CD3+ T cells were significantly downregulated, while both Ti/Th cells (CD3+CD4+) and Ts/Tc cells (CD3+CD8+) were inhibited in tumors of the HBO group. The percentage of regulatory T cells in Ti/Th (CD3+CD4+) cells was elevated in the tumors and thymuses of the HBO group.

Conclusion

HBO induced ROS signaling in the thymus, inhibited CD3+ T cell generation, and facilitated malignant glioma cell growth in vivo in the intracranial glioma mouse model.
Towards a pluralist labor geography: Constrained grassroots agency and the socio-spatial fix in Dȇrsim, Turkey
Authors: Ağar Celal Cahit , Böhm Steffen
Published: May 2018

This paper explores the interplay between capital, socio-spatial structure and grassroots agency in the context of the recent trajectories of labor geography. Based on field research conducted in Dȇrsim, Turkey, our analysis unfolds the constraining role of socio-spatial structure in the agency and praxis of grassroots movements and their geography-making and crisis-displacement from below. Through the case study, we propound a concept of socio-spatial fix to explain how this praxis conjoins with and assists capital in both staving off its recurrent crises and reproducing its own logic of accumulation. Our analysis reveals that the socio-spatial fix in Dȇrsim, which is constituted by the grassroots struggle against hydroelectric power plant projects, performs three functions. First, it facilitates the production of capitalist social relations and spaces; second, it strengthens and maintains the existing social order through temporally moderating the province’s chronic problems; and third, it provides legitimacy for the capitalist exploitation of nature, culture and histories. Our research contributes to the emerging pluralist school of labor geography, providing an empirically substantiated insight into how capital reproduces itself via socio-spatial fixes produced by constrained grassroots agency.
Aging Effect on Mechanical Characteristics of Bituminous Mixtures
Authors: Said Safwat F.
Published: May 2018

Traditionally, asphalt concrete requirements are based on recipe specifications for bituminous mixtures; these specifications do not consider changes in the mechanical properties of materials over time. A considerable hardening of bitumen occurs with age, a characteristic that must be considered in the evaluation of bituminous materials. In asphalt concrete evaluation work, such as pavement design or end-product contracts, the age of asphalt materials may have a considerable impact on the outcome. This investigation was undertaken to aid the development of a performance specification that is based on the structural functional properties of asphalt concrete. Properties of asphalt concrete cores from various road sections were evaluated with respect to changes in stiffness and creep over several years, with an emphasis on hardening during the early life of the pavement. Relationships between mechanical properties of bituminous mixtures and age have been established. The results make it possible to take into account the effect of aging during pavement evaluation and during characterization of mixes with respect to aging properties. It was shown that stiffness modulus and creep deformation of bituminous layers can change significantly during the early life of the pavement and that this change should be considered in performance specifications and pavement analysis.
Verification and Improvement of the Rate of Asphalt Aging Simulated by AASHTO PP1–98 Protocol
Authors: Raghavendra Suresh , Zapata Claudia E. , Mirza M. Waseem , Houston William N. , Witczak Matthew W.
Published: May 2018

It is well documented that environmental effects play a significant role in characterizing material properties, which in turn affect pavement performance. Studies under the Strategic Highway Research Program (SHRP) were carried out on the age-hardening characteristics of asphalt binders and mixes. As a result, laboratory procedures to simulate the field hardening of asphalt binders and mixes, AASHTO Provisional Protocols PP1–98 and PP2–99, were developed. The approaches followed in these procedures are of great value for the ongoing research on pavement aging; however, due to limited resources and time constraints under the SHRP program, these provisional procedures have certain limitations. A research study, NCHRP Project 9–23, was initiated to overcome these limitations and enhance the predictive capabilities of these protocols. The current research paper is a part of NCHRP 9–23, which deals with the PP1–98 protocol. Binders and field cores were obtained from long-term pavement performance and other sites across the United States. Original, laboratory-aged, and field-aged binders were characterized through dynamic shear rheometer testing. The existing protocol was verified; on the basis of the findings, the protocol was improved to include the effect of field aging conditions and mix properties. The developed model was calibrated and validated with field data. Parametric analysis was performed on the final model to ascertain the practicality of the output. On the basis of those findings, a recommended provisional protocol was developed. The recommendations apply only for conventional, nonmodified binders.
Firm Relocation and Accessibility of Locations
Authors: De Bok Michiel , Sanders Frank
Published: May 2018

This paper describes the empirical results of the estimation of discrete choice models for the location decision of moving firms in a spatial disaggregated environment. Systematic choice sets are applied to account for the choice context of each relocated firm. Each location alternative is described by a set of spatial attributes, including accessibility variables and the migration distance between the origin of the moving firm and the alternative. The firms analyzed are categorized by their mobility profile. These mobility profiles are homogeneous groups of firms with similar mobility characteristics. The models are estimated on an extensive revealed-preference data set with firm migration observations between 1988 and 1997 in the province of South Holland in the Netherlands. The results indicate that it is essential for modeling the spatial behavior of relocating firms to account for the original location. The accessibility of locations appears to be of modest importance in the location preference of firms; measures describing the distance to transport infrastructure appear to have the most significant influence. Finally, distinctive taste preferences are observed in firms with different mobility profiles and of different sizes.
Intercity Variations in the Relationship between Urban form and Automobile Dependence
Authors: Zhang Ming
Published: May 2018

This study was motivated by the need for more empirical research on the urban form–travel connection. A two-tiered travel effect is expected from strengthening the urban form–travel connection: the enhancement of access to choices and a shift in travel mode choice from driving to nondriving. Existing studies have focused primarily on the second-tier effect but have largely omitted the first. This study attempted to fill that gap. Through joint-logit modeling of choice set formation and travel mode choice in three cities–-Boston, Massachusetts; Portland, Oregon; and Houston, Texas–-the study measured the degree of automobile dependence in the three cities. It also estimated elasticities of automobile dependence and of driving probabilities with respect to land use densi-fication, transit access improvement, and control of motorization. There were large variations in the levels of automobile dependence and their elasticity estimates among the three cities. Public policies aimed at reducing automobile dependence should be formulated and evaluated based not just on the final outcome of modal split but also on the provision of travel options to travelers. As cities differ in their existing urban forms, currently available transportation services, and prevailing preferences of travel, it is important to recognize that the same set of policy strategies implemented in different cities is unlikely to generate the same level of effects in reducing automobile dependence.
Modeling Long-Range Transportation and Land Use Scenarios with Citizen-Generated Policies in the Sacramento, California, Region
Authors: Johnston Robert A. , Gao Shengyi , Clay Michael J.
Published: May 2018

The Sacramento, California, region has been engaged in an innovative long-range visioning process in 2004 and 2005; the regional transportation planning agency is defining and modeling several 50-year growth scenarios. The authors worked with environmental and social equity citizens’ groups to define policies that would reduce emissions, serve lower-income travelers better, and preserve habitats and agricultural lands in the region. The citizens’ groups rejected the new freeways planned for the region as well as the substantial freeway widenings for high-occupancy vehicle lanes. In addition, they defined a more ambitious transit system, involving new bus rapid transit lines and shorter headways for all rail and bus service. This transit-only plan was modeled by itself and along with a land use policy for an urban growth boundary and a pricing policy for higher fuel taxes and parking charges for work trips. A new version of the MEPLAN model was used to simulate these scenarios over 50 years, and findings about total travel, mode shares, congestion, emissions, land use changes, and economic welfare of travelers are described.
Planning and Design of a Taxipooling Dispatching System
Authors: Lee Ker-Tsung , Lin Da-Jie , Wu Pei-Ju
Published: May 2018

Shifting people from driving to using public transportation has been important in alleviating urban traffic congestion. Intelligent transportation system technologies applied to public transportation can provide useful data to system operators and users and increase the use and productivity of high-occupancy vehicles. Integration of metropolitan rapid transit, feeder buses, and taxipooling can attract more public transportation users. Advanced taxipooling transfer assignment systems, a type of advanced public transportation systems program, aims to apply advanced technologies to taxi operations, including dynamic taxi fleet management, taxipooling strategies, and safety monitoring systems. Success in using taxis as a feeder service to mass transit systems requires advanced information technologies such as the Global Positioning System, geographic information systems, wireless communications, and, most important, an efficient taxi dispatching algorithm. The objectives and background of a dedicated taxipooling fleet in a metropolitan area are given. Also, a real-time, two-step taxipooling dispatching system is presented. A case study with parameter values obtained from Taiwan is explained; the simulation result is interpreted to illustrate the feasibility of the algorithm. Sensitivity analysis proves the robustness of the dispatching algorithm and shows the flexibility decision makers can have to serve certain purposes. Assumptions and constraints of the proposed dispatching system are evaluated, and the possibility of system expansion is discussed.
Effect of Taxi Information System on Efficiency and Quality of Taxi Services
Authors: Kim Hyunmyung , Oh Jun-Seok , Jayakrishnan R.
Published: May 2018

In many major metropolitan areas, taxi services have played an important role as a semipublic transportation mode without public support. However, there has not been much modeling effort–-despite the importance of taxis in urban transportation systems–-mainly because of the difficulty in modeling taxi drivers’ behavior. This study models a taxi service system in urban areas, taking into account taxi drivers’ knowledge of the transportation network built from their day-to-day experience. Passenger-seeking behavior by taxi drivers is modeled on the basis of their expected travel time and expected waiting time. The model considers the stochastic and dynamic transportation network and various levels of network knowledge on the part of drivers. This modeling approach provides flexibility in modeling the characteristics of taxi operation as well as understanding how taxi drivers’ capability evolves. The study analyzes the fleet size of taxi service systems and the effects of the taxi company's information systems by considering quality and operational efficiency of taxi services, from both the passengers’ and taxi operators’ points of view. A simulation experiment shows that the taxi information system can provide benefits equivalent to increasing the number of taxis by 20% in regard to the quality of taxi service.
Transition from Guardrail to Concrete Bridge Rail for Low-Speed Roadways
Authors: Bligh Roger P.
Published: May 2018

In recent years, many state departments of transportation have had to modify their approach guardrail–to–concrete bridge rail transition systems to comply with the testing requirements of NCHRP Report 350. Generally, these transition systems are designed and tested for use on high-speed roadways. Because no national transition designs have been developed and tested for lower-speed conditions, the same transition standard is typically applied to all roadways regardless of speed. The new transition designs represent a significant increase in installation cost and complexity over some previous designs that were acceptable under NCHRP Report 230. Thus, it may be cost-prohibitive to require use of the same design on all roadways. The purpose of this research was to develop a guardrail–to–concrete bridge rail transition that is suitable for use on lower-speed roadways and that is less expensive and complex than current designs for high-speed roadways. A low-cost transition was successfully evaluated under NCHRP Report 350 Test Level 2 (TL-2) impact conditions. It is considered suitable for use on roadways that have traffic conditions appropriate for the use of TL-2 safety hardware. Use of this system provides significant savings in material and installation cost compared with high-speed (i.e., TL-3) transitions.
Development of Hybrid Energy-Absorbing Reusable Terminal for Roadside Safety Applications
Authors: Sheikh Nauman M. , Alberson Dean C. , Bullard D. Lance
Published: May 2018

The hybrid energy-absorbing reusable terminal (HEART) is a newly developed crash cushion or end terminal to be used in highway safety applications to mitigate injuries to occupants of errant vehicles. HEART is composed of corrugated plates of high–molecular weight, high-density polyethylene (HMW-HDPE) supported on steel diaphragms that slide on a fixed rail. Kinetic energy from errant vehicles is converted to other energy forms through folding and deformation of the HMW-HDPE material. Many previous designs utilized plastic or permanent deformation of plastics or steels to accomplish this goal. However, HEART is a combination of plastic and steel that forms a largely self-restoring and largely reusable crash cushion. Consequently, HEART has a major life-cycle cost advantage over conventional crash cushion designs. HEART was developed through extensive use of finite element analysis with LS-DYNA. The simulation approach adopted for the development of HEART, construction details, and a description and results of crash tests performed so far to evaluate its performance are presented. Also discussed is some of the follow-up work currently under way for approval of HEART by FHWA as an acceptable crash cushion for use on the National Highway System.
Sequential Kinking and Flared Energy-Absorbing End Terminals for Midwest Guardrail System
Authors: Bielenberg Robert W. , Sicking Dean L. , Rohde John R. , Reid John D.
Published: May 2018

The Midwest guardrail system (MGS), developed at the Midwest Roadside Safety Facility, was designed to improve the performance of traditional strong-post, W-beam guardrail systems. These improvements include decreasing the potential for rollover with high center-of-gravity vehicles, decreasing the potential for rail rupture at the splice locations, and decreasing the sensitivity of the system to the installation rail height. However, safe guardrail termination options for the MGS must be developed before the system can be implemented on the roadside. Two end terminal designs, the sequential kinking terminal (SKT) and the flared energy-absorbing terminal (FLEAT), were partially redesigned and crash tested in conjunction with the MGS according to NCHRP Report 350 criteria. The new versions of the terminals were named the SKT-MGS and the FLEAT-MGS to designate them for use with the MGS. To evaluate the performance of the terminals with the MGS, a series of four full-scale crash tests was conducted: two redirection tests, NCHRP Report 350 Test Designations 3–34 and 3–35, and two head-on impacts, Test Designations 3–30 and 3–31. The results from the four crash tests were found to meet all relevant safety requirements. The SKT-MGS and FLEAT-MGS end terminals are the first successfully tested end terminals for use with the MGS.
Deception Pass Log Rail in Washington State
Authors: Jepperson Omar W. , Williams William F. , Albin Richard B. , Bullard D. Lance
Published: May 2018

Washington State Route 20 (SR-20) in Northwest Washington passes through the Deception Pass State Park. The portion of SR-20 within the park was constructed by the Civilian Conservation Corps (CCC) in the mid-1930s. As part of this work, the CCC built a stone masonry bollard and log rail system to delineate the edge of the road and prevent early-model vehicles from leaving the roadway. Because of their age, quality of workmanship, and importance to the surroundings, the park's bridges and log rail are eligible for the National Register of Historic Places. Previous attempts to replace this rail with a crashworthy system were unsuccessful because of the concern that the aesthetic and historic integrity of the park be preserved. A new approach adopted by the Washington State Department of Transportation began with understanding the context of the highway and the concerns of the other stakeholders. In addition, the stakeholders were educated on the safety issues. As a result, a solution was developed and was acceptable to all. The primary solution involved the development of a new barrier that replicated the appearance of the original log rail. This barrier was crash tested in accordance with NCHRP Report 350 TL-2 criteria and is available for use at other locations at which an aesthetic barrier is desired.
Mass Loading of First Flush Pollutants with Treatment Strategy Simulations
Authors: Kayhanian Masoud , Stenstrom Michael K.
Published: May 2018

“First flush” is a term for the initial period of stormwater discharge from a storm event. Conventional thinking is that the first flush exhibits high pollutant concentrations. The existence of a first flush in highway runoff has been documented through a comprehensive 4-year runoff monitoring from three highway sites in Los Angeles, California. As part of this study, a numeric definition of the mass first flush ratio is developed; it characterizes the normalized mass of pollutants in the first portion of the normalized runoff volume. Mass first flush ratios have been developed for more than 30 conventional water quality parameters, heavy metals, nutrients, and organic pollutants. This study explores the improved performance that some best management practices (BMPs) exhibit when they can take advantage of the high concentrations of pollutants at the beginning of a storm event. A range of hypothetical events corresponding to the observed mass first flush ratios were simulated. These simulations demonstrate that improved mass removal rates are possible when BMPs can be managed to treat a greater volume of the early runoff. For example, it was shown that for pollutants such as total suspended solids, chemical oxygen demand, total organic carbon/compounds, and oil and grease, infiltration basins that can capture the first 20% of the storm volume and bypass the remaining volume can be twice as effective as a practice that treats 20% of the storm volume throughout the entire period of runoff. Similarly, when a seasonal first flush exists, treating the first few storms of the season entirely is more effective than treating a constant volume throughout the season.
Asphalt Pavement Rehabilitation Treatment
Authors: Morian Dennis A. , Zhao Yanqing , Arellano Janice , Hall Donald E.
Published: May 2018

The condition of pavements in northwestern Pennsylvania was extremely poor in the early 1980s. Several methods of pavement rehabilitation of asphalt-surfaced highways were used to improve pavement performance and the management of pavement investment. This paper analyzes the performance of a number of these sections after 21 years. The results from the analysis show that, relative to conventional milling and leveling with placement of an overlay, the appropriate application of stress-absorbing membrane interlayers (SAMIs) and of cold in-place recycling has been effective for both performance and relative cost-effectiveness. The analysis also shows that for a subsequent generation of rehabilitation, the benefit of these treatments continues to be evident. As a result of this study, it is recommended that highway owners seriously evaluate rehabilitation treatments other than conventional milling and leveling with placement of an overlay. The performance of SAMI and cold-recycled sections in this instance has more than justified the additional expense of the construction.
Accelerated Pavement Rehabilitation and Reconstruction with Long-Life Asphalt Concrete on High-Traffic Urban Highways
Authors: Lee Eul-Bum , Lee Hojung , Akbarian Massod
Published: May 2018

Rehabilitation of urban highways is a critical issue confronting the California Department of Transportation because the state has a significant inventory of overaged, heavily trafficked urban highways showing extensive signs of distress. This paper presents the innovative pavement rehabilitation technologies and techniques that the agency applied in the first asphalt concrete (AC) project for its Long-Life Pavement Rehabilitation Strategies (LLPRS) program. A 4.4-km stretch of deteriorated concrete pavement on I-710 in Long Beach was rehabilitated successfully with 230 mm of AC overlay or 325 mm of full-depth AC replacement during eight 55-h weekend closures. The pilot project proved that the accelerated (fast-track) rehabilitation with 55-h weekend closures is a viable option that can drastically shorten the overall construction time and lessen the negative effects of construction in an urban area. The project also proved that AC pavement designed to provide a design life of 30-plus years can be constructed in a series of weekend closures even on the most heavily loaded truck route in the state. The construction-monitoring study indicated that contractor productivities were noticeably improved (through the learning effect) as weekend closures were repeated. In addition, the pay factor clause in the contract effectively encouraged the contractor's awareness of quality. The traffic measurements study showed that traffic operated at free-flow speeds throughout the surrounding highways and arterial roads during the construction weekends. It is expected that the construction and traffic management techniques adopted in this project will be used in LLPRS projects on California urban highways with high-traffic volumes.
History and Development of U.S. Procedures for Falling Weight Deflectometer Calibration
Authors: Irwin Lynne H. , Richter Cheryl A.
Published: May 2018

In 1988 the Strategic Highway Research Program purchased four falling weight deflectometers (FWDs). During the acceptance testing it became evident that an improved procedure for calibration was needed to determine whether the specifications for the precision and the accuracy of the sensors were achieved. The authors were responsible for developing the procedure. This paper reports on the steps taken during the development of the calibration protocol. The reasons underlying the equipment and the procedures chosen are discussed. The sources of error in FWD measurements are identified, and ways that have been used to reduce those errors are reported. The goal was to reduce the systematic (bias) error to less than 0.3% through calibration. This level of error ensures that the random measurement error is larger than the systematic error for all pavement deflections less than 600 μm [24 mils (1 mil = 0.001 in.)]. Experience has shown that most highway pavements deflect less than 600 μm. The effects of FWD measurement errors on backcalculated pavement moduli are briefly reviewed. Verification of the protocol by several means showed that the calibration goal was achieved. Subsequent experience with the calibration protocol has shown that it has been effective and that it ensures high quality in the FWD data.
Urban Freight in Dublin City Center, Ireland
Authors: Finnegan Clare , Finlay Hugh , O'Mahony Margaret , O'Sullivan Donal
Published: May 2018

Findings are presented from a study evaluating sustainable freight distribution in the city center of Dublin, Ireland, particularly focusing on urban distribution centers (UDCs) and managing the last mile of deliveries. A survey of city center organizations is described, and relevant delivery patterns (origin, destination, type of goods delivered) are compared with those from a previous feasibility analysis to determine UDC opportunities in Dublin. A real-life commercial example of a UDC is also described. Ireland's largest grocery distributor operates this UDC. The operational efficiencies and the wider benefits of the UDC are discussed. In addition, a commercial example of managing the last mile of deliveries through a city center delivery platform is detailed. The delivery platform is managed by a leading logistics service provider.
Off-Peak Freight Deliveries
Authors: Holguín-Veras José , Polimeni John , Cruz Brenda , Xu Ning , List George , Nordstrom Jeana , Haddock Jorge
Published: May 2018

This paper summarizes research conducted on private-sector stakeholders’ perceptions of the challenges and potential of off-peak deliveries to congested urban areas. Information is presented from a comprehensive outreach program that involved focus groups, in-depth interviews, and Internet surveys. On the basis of the insights gained into the dynamic interactions among stakeholders, the corresponding policy implications and chief conclusions of the research are discussed.
Multiobjective Optimization for Hazardous Materials Transportation
Authors: Huang Bo , Fery Pierre , Zhang Liangpei
Published: May 2018

This research attempted to build a framework for determining optimal routes for hazardous materials transportation. Previous work has suggested the incorporation of many conflicting objectives in the analysis, such as travel cost, population exposure, environmental risk, and security concerns. Multiplying the number of objectives leads to complex shortest path problems that often have several efficient solutions. The present study emphasizes an overview of possible trade-offs among routes without generating all of them. A simple characterization of the efficient routes is used to select the best ones with no need for input from the decision maker. A case study with eight objective functions was performed on a road network in Singapore. A geographical information system was used to quantify road link attributes, which are assumed linear and deterministic for the sake of simplicity. The proposed algorithm derives four significantly different routes, which conform to intuition.
Capacity Modeling in Transportation
Authors: Park Minyoung , Regan Amelia
Published: May 2018

A conceptual framework is presented for modeling the capacity of multimodal freight transportation networks. A review is provided on the evolution of capacity models for use in transportation systems planning and investment, and recent advances toward a system-oriented, multimodal capacity model are discussed in depth. A logical network capacity model based on bilevel programming is proposed.
Investigation of the CoreLok for Maximum, Aggregate, and Bulk Specific Gravity Tests
Authors: Sholar Gregory A. , Page Gale C. , Musselman James A. , Upshaw Patrick B. , Moseley Howard L.
Published: May 2018

The Florida Department of Transportation uses long-established test procedures to determine the maximum specific gravity (Gmm) and bulk specific gravity (Gmb) of asphalt mixtures and the bulk specific gravity (Gsb) of aggregates. The CoreLok, a vacuum-sealing device that can be used to determine these properties, was evaluated by the department for these test procedures. With respect to the Gmm test procedure, for mixtures containing nonabsorptive granites, the CoreLok determined results equivalent to those of the department's test procedure. However, for mixtures containing absorptive limestones, the CoreLok determined higher Gmm values than did the department's test procedure. The apparent reason for the discrepancy is that the CoreLok does not determine a saturated surface dry condition of the sample. With respect to the aggregate specific gravity test procedures, the CoreLok provided test results equivalent to the department's test procedure for the nonabsorptive fine aggregates only. For the absorptive fine aggregates and all of the coarse aggregates, the CoreLok determined Gsb test results significantly different from those of the department's test procedures. The CoreLok may be suitable for determining Gmb for coarse-graded compacted specimens with high porosity and air voids. There are concerns with the accuracy of the CoreLok results because of the bridging effect of the plastic bag over the large surface voids and because of the CoreLok's significant underestimation of the specific gravity of a solid aluminum cylinder.
Arterial Interchange
Authors: Eyler Dennis R.
Published: May 2018

A family of interchange designs has been developed for arterial roadways that will not become freeways. These designs are compact and inexpensive. A critical feature that makes the designs unsuitable for freeways is that each roadway would have at-grade intersections. Called arterial interchanges, these designs are needed because traffic growth has caused the major intersections on many arterial roadways to reach capacity. Those intersections often have three through lanes and double left-turn lanes, and now triple left-turn lanes are in use. Large intersections are a problem for pedestrians and for signal control. These large intersections experience high crash rates and traffic delays. The limits for at-grade intersections have been reached. What is next if traffic grows? Conversion to a freeway is the traditional solution, but this is expensive, time-consuming, and often opposed. Adding through lanes is also expensive and an inefficient way to increase the capacity of a few intersections. Often, congestion at only one intersection controls the capacity of a corridor. If a freeway interchange design is used, new problems are created, including weaving, loss of access, and added right of way. The arterial interchange concept, if used along an entire corridor, will create a new type of arterial roadway that will provide 75% of the benefits of a freeway with only 50% of the impact. The arterial interchanges were analyzed with the use of traffic simulation (VISSIM), and those results, along with the estimated construction costs, are presented.
Robustness of Efficient Passenger Boarding Strategies for Airplanes
Authors: Ferrari Pieric , Nagel Kai
Published: May 2018

Common wisdom is that airplanes make money only when they are in the air. Therefore, turnaround time (turn time) on the ground should be reduced as much as possible. An important contribution to the turn time is airplane boarding time. Many different schemes are in use, from random seat selection to sophisticated boarding groups. A simulation model is described to evaluate different boarding strategies. In contrast to earlier work, it puts special emphasis on disturbances, such as a certain number of passengers not following their boarding group but boarding earlier or later. A surprising result of this work is that the typical back-to-front boarding strategy becomes improved when passengers do not board with their assigned group. Other proposed strategies still consist of small numbers of boarding groups but are both faster and more robust with regard to disturbances.
Stated Preference as a Tool to Evaluate Airline Passenger Preferences and Priorities
Authors: Whitaker Bethany , Terzis George , Soong Eddie , Yeh Wayne
Published: May 2018

Stated preference (SP) analysis is a technique widely used by market research and transportation professionals to understand decision-making behavior and consumer choice models. This discussion covers the role of SP as a tool to enhance understanding of air travelers’ preferences and priorities for airline services and the potential for SP research to play a greater role in product development and demand forecasting for different types of airline services. Two case studies of previously conducted research for a major airline in Asia are used to explore how SP data have been used to evaluate passenger preferences and priorities. SP experience gained from other transportation modes (e.g., urban rail and bus services) is also examined and the potential applications of these lessons to the airline industry are suggested.